Mercedes-Benz Gls450 vs Lexus Gx550

What's the difference?

The GLS450d impresses as an entry-level grade, as it’s a more family-friendly allrounder than the specialised AMG and Maybach variants. Its combination of a torque-rich diesel 48V hybrid drivetrain, air-cushioned suspension and plush interior are as well suited to luxury urban travel as they are to grand touring, where its heavy towing and generous load-carrying capabilities can shine. Whether it’s worth around $200K drive-away, only those who shop at the top end of town can decide.

The new Lexus GX 550 Sports Luxury looks fantastic and has enough mod cons to satisfy a family but it’s not as luxurious as you’d expect from a premium brand and the fuel economy and driving range will turn off some. But if you’re still interested, there’s a lot here that will make you happy and it’s one of the smoothest 4WDs I’ve driven.

This is an imposing vehicle in extravagant S-Class tradition, riding on an expansive 3135mm wheelbase and stretching more than 5.2 metres (5215mm) long and more than 2.0 metres (2030mm) wide with a turning circle that's nudging 13 metres.

However, it’s just under 1.8 metres (1798mm) tall, so there’s no clearance issues when accessing multi-storey carparks. And with its side-steps (or ‘running boards’ in nostalgic Benz speak) most adults can step rather than climb aboard, although passengers of shorter stature during our test noted that assist handles on the A and B pillars would be handy.

Central to its sophisticated chassis design is adaptive air suspension, which uses a pneumatic or ‘airbag’ form of springing with adaptive damping to continuously optimise ride comfort and handling response according to road conditions and driving dynamics (see Driving).

The GLS’s styling is clean and uncluttered with tasteful restraint evident in its chrome and satin-chrome highlights, yet it projects a majestic quality with its prominent four-louvre grille and elegantly spoked alloy wheels.

The spacious and sumptuous seven-seat interior is visually pleasing and practical, with a subtle blend of surface treatments, contrasting tones, lots of soft-touch surfaces and exposed stitching. This is combined (thankfully) with physical dials, switches and ‘piano key’ buttons to control numerous interior functions, in preference to distracting touchscreen prompts.

The new GX 550 looks massive and while it shares the same platform as the Toyota LandCruiser 300 series, it doesn't share all of its bulk. They both stand at 1980mm wide but differ on length (5015mm vs 4980mm) and height (1670mm vs 1950mm), respectively.

The new design is fabulously rugged but each body panel looks meticulously crafted and is just the right size. This just means the proportions look right and your eye sort of glides over the big body rather than stopping on any one feature.

But having said that, there are a lot of nice features to focus on, like the long LED headlights and rear strip light, auto-folding side steps, 22-inch alloy wheels and sharply styled rectangular side mirrors.

The tailgate window can also be opened if you need to pop something into the boot but don't want, or have the space, to open the tailgate itself.

The styling takes a minor nose dive once you hit the cabin, though, because it doesn't look as sumptuous as you'd expect in a premium SUV.

I love the utilitarian and military vibe of the vertical dashboard, chunky air vents and relatively small windscreen. It looks great but some trims are plasticky and the touchpoints, while soft, are not Lexus-plush.

However, the technology looks gorgeous with an integrated 14-inch multimedia display and a 12.3-inch digital instrument cluster. The fixed sunroof with its two settings (clear or opaque) is also a lovely feature.

But on a whole, the GX 550's European rivals outclass it with their flashier cabins.

Although it has a hefty 2655kg kerb weight, our test vehicle’s 3420kg GVM rating provides a useful 765kg of load capacity, which should comfortably absorb the combined weight of up to seven occupants and light luggage. Or with the third row of seating folded, five occupants and heavier luggage.

It’s also rated to tow up to 3500kg of braked trailer and with its sizeable 6920kg GCM (or how much weight it can legally carry and tow at the same time) it can carry its maximum load while towing its maximum trailer weight.

So, that’s commendable practicality, given it would be well suited to owners that need to tow large caravans, boat trailers, horse floats etc in style without having to compromise much (if at all) on either passenger numbers or luggage capacity.

Driver and front passenger space and comfort is exceptional, as you’d expect. Storage includes a large glovebox plus a bottle holder and bin in each door. The front of the centre console has two USB-C ports, wireless phone charging and heated cupholders, while the rear of the console has a large storage box with a third USB-C port and padded lid that doubles as a comfy elbow rest.

Even tall passengers in the second row of seating enjoy spacious comfort, given I’m 186cm and with the driver’s seat set in my position I have ample knee clearance, foot room and head space.

However, the central passenger must contend with a transmission tunnel in the floor and shoulder room would be squeezy for three large adults, which is okay for short trips but a maximum of two would be ideal for longer journeys.

The rear of the centre console also treats second-row passengers to a pair of USB-C ports, adjustable air-vents and a control panel that allows independent climate adjustment.

There’s also a large bin/bottle holder in each door plus storage nets on each front seat backrest. The centre seat backrest folds flat to allow long items (skis etc) to slot between the outer backrests. And it also serves as a fold-down armrest, containing two cupholders and a lidded slimline compartment that’s ideal for hidden phone storage.

The third row is uncommonly spacious, even for tall people, with padded armrests on each side containing cup holders and twin USB-C ports.

The carpeted rear luggage area has four load-anchorage points, a first aid kit and 12v socket. With the third-row seats upright it offers 355 litres of load volume, which increases to 1350 litres with the third row folded and 2400 litres (or 2.4 cubic metres) with both the second and third rows folded.

The cabin of the new GX 550 is fairly practical with plenty of head- and legroom in each row (yep, even the third!). When you first hop in, it can feel a big snug on elbow-room but this feeling quickly dissipates.

Despite a 215mm ground clearance, access is pretty good for the front and middle rows due to the wide door apertures and side-steps. Third row access is a bit awkward for an adult but my eight-year old loved scampering back there this week.

The electric front seats are comfortable with their extra functions and I like the way the massage feature extends to the seat cushion as it limits fatigue on longer journeys. However, you sit on top of them rather sink into them which makes it feel a little trucky at times.

The wide middle row has a bench seat that will be comfortable for kids but an adult might get a sore behind on a long trip. The transmission tunnel also compromises foot room for adults but the seat is wide enough to make use of all three top-tether anchor points (there are ISOFIX mounts too).

It was a little bit of an effort to lift my big booster seat into the back because the GX 550 sits so tall but otherwise, there's plenty of room around a child seat for them not to feel like a sardine.

Individual storage is made up of a glove box that fits an owner's manual, a small shelf in the dashboard and a middle console that doubles as a cool box (mini fridge) and can fit up to four cans or bottles in it.

Each row gets four drinkholders and two USB-C ports but the front also enjoys a 12-volt socket and wireless charging pad. There's a 220V domestic plug port in the boot for larger appliances, too.

It's sometimes awkward to use the wireless charging pad because it's easy for your phone to slide around on it and it quite often disengaged from charging.

My son enjoyed all of the other amenities in the middle row, like the reading lights, climate control, two USB-C ports and retractable sunblinds and I applaud carmakers when they position rear directional air vents in the pillars and/or roof. It just makes it so much easier to cool down sweaty kids!

The 14-inch multimedia display has clear graphics and a responsive touchscreen. The layout is easy enough to get used to after spending some time with it and the sat nav is simple to use.

I like that the sat nav directions can be pulled into the 12.3-inch digital instrument cluster and head-up display.

There is a Lexus connected services app, which you get a three-year subscription to. It's easy to connect to the wireless Apple CarPlay and there is also wireless Android Auto.

The system also has Bluetooth and digital radio, which is a delight to use through the 21-speaker Mark Levinson sound system.

The cabin is rounded out by the well-shaped boot which has a massive 1063L of capacity when the third-row is folded. That's been more than enough for my family's needs this week and my German Shepherd was pretty comfy back there, too. The powered tailgate has a kick-function and there is a full-size spare wheel underneath the car.

The Lexus GX 550 shares the same platform as the recently introduced Toyota Prado but both models are now based on the same 'body-on-frame' platform shared by the beastie Toyota LandCruiser 300 Series. So it's bigger and features a more rigid chassis than before.

Surprisingly, that hasn't translated to a massive price tag for the GX 550 and you can pick up the flagship grade on test for this review for $128,200, MSRP.

Which sounds inexpensive when you compare it to the BMW X7 xDrive 40i M Sport which is priced from $171,300 MSRP but the Land Rover Defender 110 P400 X-Dynamic HSE is a lot closer at $128,815 MSRP.

The only issue here is that shared platform, because while they don't share the same powertrain, the flagship Toyota Prado Kakadu ($99,990 MSRP) is still almost $30K more affordable and boasts a similar equipment list. So, ask yourself, is it the brand and engine you're after or the new good looks?

The standard equipment is well-rounded with a 14-inch touchscreen media display with satellite navigation and wireless Apple CarPlay and Android Auto.

A fully digital 12.3-inch instrument cluster, colour head-up display, three-zone climate control and a 21-speaker Mark Levinson sound system round out multimedia requirements.

Other technology includes a digital rear view mirror, two USB-C ports in each row, a 12-volt socket, a 220-volt domestic outlet and a wireless charging pad.

There are two particularly handy features for families, the 'cool box' (basically a mini fridge) middle console and rear retractable sun-blinds.

The fixed panoramic sunroof features two settings allowing you to make it clear or opaque. The electric front seats feature heat, ventilation and massage functions and the rear outboard seats are heated as well. The third row electrically adjusts and there are multiple buttons throughout the car to access this feature.

Upgraded leather-accented upholstery is standard in the flagship grade and is available in three combinations. The Sports Luxury also features 22-inch alloy wheels, a full-size spare wheel and a powered tailgate with kick-function.

The GLS450d comes standard with a 3.0-litre turbocharged inline six-cylinder diesel producing 270kW of power at 4000rpm and 750Nm of torque between 1350-2800rpm.

This is paired with a 48V mild-hybrid system comprising a 48-volt battery (charged by regenerative braking) and an integrated starter-generator which provides both seamless engine stop-start and up to 15kW/200Nm of extra power and torque during acceleration.

A nine-speed torque converter automatic provides the choice of manual shifting using the steering wheel-mounted paddles, along with several selectable drive modes.

The active all-wheel-drive system continuously adjusts the engine’s torque delivery between front and rear axles (and individual wheels as needed) to maintain optimum traction and handling.

All GX 550 grades share the same 3.5L V6 twin turbo-petrol engine which produces up to 260kW of power and 650Nm of torque.

This 4WD has high- and low-gearing, as well as a bunch of driving modes to suit most occasions, like 'Eco', 'Comfort', 'Sport' and 'Sport+'.

The 10-speed automatic transmission shifts through its gears smoothly and it always feels like it's engaged in the right gear. Which isn't always the case for a big SUV!

The Sports Luxury is fitted with a towing hitch and cover but unlike the base Sports grade which has a 3.5-tonne braked towing capacity, this model only has a 3130kg capacity which might not appeal to families with big toys to tow. 

Mercedes-Benz claims official combined consumption of 7.8L/100km and the dash display was showing 9.0 when we stopped to refuel at the completion of our 368km test, which included the usual mix of suburban, city and highway driving with up to five passengers at times and light luggage.

Our own figure, calculated from fuel bowser and tripmeter readings, was close at 9.5 which is outstanding sub-10L/100km economy for such a substantial vehicle in mostly metropolitan use. Therefore, based on our own consumption figure, you could expect a real-world driving range of around 950km from its 90-litre diesel tank.

I didn’t have high hopes for fuel economy because the official combined (urban/extra-urban cycle figure is a hefty 12.3L/100km but after mostly open-road driving, with some urban stuff mixed in, my real-world average came in at 11.8L.100km! This figure is based on my actual km travelled (358km) and litres of fuel used (42.41L).

While I’m surprised by the fuel usage result, I wouldn’t say this car has good fuel economy compared to its diesel-powered counterparts but it’s not terrible!

The GX 550 has a relatively small fuel tank compared to its Toyota cousins at 80L and based on the combined fuel cycle, you’ll get a theoretical driving range of up to 650km.

Not all that great. Not for a big family mover and not if you’re typically driving in the city, where fuel usage will be a lot higher.

The GX 550 only accepts premium unleaded petrol (95 RON), too.

It’s an enjoyable vehicle to drive, with multiple power adjustments for the seat and steering wheel combined with a large left footrest which provide supreme driver comfort and support.

The powerful and responsive turbocharged six-cylinder diesel and nine-speed auto are well suited to this application. The engine’s ample torque provides spirited acceleration from standing starts, taking only six seconds to reach triple-digit speeds.

This drivetrain would be well suited to heavy towing duties, given the 48V mild-hybrid system can contribute an extra 200Nm (in addition to the engine’s 750Nm), which raises the total theoretical torque output to almost 1000Nm.

The active air suspension provides a wonderfully cushioned ride that floats over bumpy roads, while maintaining excellent handling response and surprising agility. These commendable chassis dynamics, combined with the powerful and responsive drivetrain, makes the vehicle feel smaller and lighter than its dimensions and kerb weight would suggest.

Overall, it’s difficult to fault from a driver’s perspective, with the only exception being the voice activation function. This is often triggered by words or phrases other than ‘Hey Mercedes’ resulting in regular interruption of conversations. This needs some fine tuning.

Oh my goodness the Sports Luxury is a masterclass on 4WD refinement! You never feel the bulk or weight of this massive SUV when you’re driving it. The power delivery is effortless and there’s lots of grunt available when you hit hills.

The handling is also very good with responsive steering and enough road feedback as a driver to make you feel comfortable with what the car is doing. There is some roll in corners but it can tackle more corners at speed than I thought it would. 

The high driving position makes me feel like I can see a long way ahead yet while visibility is mostly good, it can be compromised when you have the side window shades and the third row headrests up. Which is why I love the digital rear view mirror.

Overall, ride comfort is good with forgiving suspension and low cabin noise, even at higher speeds. It’s pretty easy to chat with all rows and there’s not a lot of engine noise which adds to the refinement. I do like hearing a V6 rumble but that’s just a personal preference. 

I was a little worried about hitting my local Westfield car park but this is a nimble SUV to manoeuvre and parking it is a breeze with the 360-degree camera system and parking sensors. 

The new GX 550 hasn’t been tested by ANCAP and is unrated but its cousin, the Toyota Prado, which shares the same platform just achieved a maximum five-star rating from assessment in 2024. It's fair to expect a good result for this model.

Overall, the Sports Luxury has a long list of standard safety equipment and features nine airbags which is good for a family SUV. 

Safety equipment includes adaptive cruise control, lane departure alert, lane keeping aid, traffic sign recognition, emergency steering assist, driver monitoring, safe exit assist, emergency call functionality, blind-spot monitoring, rear cross-traffic alert and tyre pressure monitoring.

The GX 550 has autonomous emergency braking (AEB) with pedestrian, cyclist, motorcyclist and junction turning assist.

The GLS comes with a five-years/unlimited km warranty (better than BMW and Lexus) and five years of roadside assistance. Scheduled servicing is every 12 months/25,000km whichever occurs first.

Mercedes-Benz offers capped-price pre-paid servicing packages with three, four or five-year terms. For example, the total upfront cost of the minimum three-year term is $4090, or an average of $1363 per service.

Lexus offers the GX 550 with a five-year/unlimited km warranty, which is fairly standard compared to its Euro rivals.

You get five years capped-priced servicing which costs $5950 but the servicing schedule is a bit of a bear at every six months or 10,000km, whichever occurs first.