Mercedes-Benz GLS-Class vs BMW X4

What's the difference?

The GLS63 is an intimidating beast from afar, but it rewards its occupants in almost every way. Yep, there really isn’t a box it doesn’t tick without serious compromise, such is its breadth of capability.

If there was ever a Swiss Army Knife of cars, the GLS63 is definitely a contender for the title, one that makes it very hard to wipe the smile off your face. Just make sure you can fit it in your garage first…

Okay, so the BMW X4 xDrive30i is neither an ass nor an elbow, to be fair, it's more of a bulky shoulder muscle, or two.

I can't say I'll ever love the X4, the idea of it is a bit too weird for me, but I can't help admiring the way it looks and the way it drives.

It's a bit like a sedan on steroids - or an SUV on a diet, depending on your perspective - but that doesn’t take away from the fact that it’s fun to drive, comfortable and retains just enough coolness, and just enough practicality, to make it worthwhile.

If the GLS63 was a Marvel superhero, it would undoubtedly be the Hulk. Simply put, it has road presence like few others. In fact, it’s frankly menacing.

Of course, the GLS is already pretty intimidating due to its sheer size and blocky design, but the GLS63’s full-fat AMG treatment takes it to another level.

Naturally, the GLS63 gets an aggressive body kit, with its purposeful bumpers, side skirts and rear spoiler serving as instant reminders of what you’re dealing with, but it’s AMG’s signature Panamericana grille insert that really hammers home the point.

Around the side, the GLS63’s 22-inch alloy wheels with staggered tyres (front: 275/50, rear: 315/45) make their presence known, positioned below the wheelarch extensions.

That said, some fun’s also had at the rear end, where the GLS63’s diffuser element integrates the foreboding sports exhaust system with quad tailpipes very neatly.

The focused Multibeam LED headlights also look the part, while the opposing LED tail-lights tie everything together outside quite nicely.

Inside, the GLS63 stands out from the GLS crowd with its sports steering wheel with Dinamica microfibre accents, and multi-contour front seats, which are covered in Nappa leather alongside the armrests, dashboard and door shoulders and inserts.

Of note, the doors bins are unfortunately of the hard plastic variety, which is very disappointing in a vehicle that costs this much. You would expect that cow hide would also been applied to them, but alas it isn’t.

The GLS63’s black headliner serves as an obligatory reminder of its sporting intent, and while it makes for a dark cabin, metallic accents are prominent throughout, while the optional trim (our test vehicle had carbon-fibre) mixes things up, alongside the ambient lighting.

And let’s not forget the GLS63 is still loaded with plenty of cutting-edge technology, including a pair of 12.3-inch displays, with one the central touchscreen and the other the digital instrument cluster.

Both are powered by Mercedes’ class-leading MBUX multimedia system and feature Apple CarPlay and Android Auto support. This set-up arguably remains the best there is today thanks to its speed and breadth of functionality and input methods.

So here's the thing. Obviously I have a personal beef with the existence of vehicles like this, but my eyes cannot deny the facts - the X4 looks fantastic. It's muscular, imposing and smooth all at once. Unlike the X6, a bigger and less visually successful attempt to play the same styling tricks with an X5, it doesn't have a ridiculous rear view that looks like it shoulders and buttocks have been fused (although it's hard to miss just how small the rear window is).

Even more impressively, there's no denying it looks better than the X3 that gave birth to it, so I can easily see why someone in a BMW showroom could be drawn to it. At least until they sit inside.

If the exterior style and eye-catching Sophisto Grey metallic paint don’t make an immediate impression then your eyes will surely widen at the interior, resplendent with bold Tacora Red seats, Aluminium Rhombicle trim finisher and the kind of sleek, classy styling that BMW excels in. 

Both the adjustable ambient lighting on the doors (we were partial to lilac) and door projectors that shot out what looked like robot wings onto the ground every time we hopped out of the X4 at night walked a fine line between futuristic cool and “parked out the front of a nightclub entrance” chintz, but over time the scales tipped more to the former. 

The big differentiator between the X4 and X3, of course, is the sloped coupé roof, a design feature that may make the X4 look a little cooler, but at the expense of cabin space, but more of that in a moment.

Measuring 5243mm, 2030mm wide and 1782mm tall with a 3135mm wheelbase, the GLS63 is an upper-large SUV in every sense of the term, which means it’s also very practical.

For example, cargo capacity below the load cover is decent, at 355L, but stow the 50/50 power-split-folding third row via the boot and it’s very good, at 890L, or drop the 40/20/40 power-split-folding middle bench, too, and it becomes a cavernous 2400L.

Better yet, the boot’s aperture is almost square, and its floor’s flat, while there’s no load lip to contend with, making loading bulkier items even easier. Up to four tie-down points are also on hand (depending on seating configuration) to secure loose cargo.

Under the false floor is the space-saver spare, which is to be expected, but what isn’t expected necessarily is the fact there’s also enough room there for the cargo cover when it’s not in use, which would be the case if six or more passengers are regularly onboard.

Moving into the power-sliding second row, the GLS63’s practicality is once again brought to the fore, with up to six-plus inches of legroom available behind my 184cm driving position.

There’s also two inches of headroom with the panoramic sunroof in situ, not to mention just enough toe-room. The GLS63’s small transmission tunnel and sheer width also mean three adults can be seated on the middle bench with few complaints.

Amenities-wise, the second row has map pockets on the front-seat backrest and a small fold-down cubby below the rear climate controls, with it containing two slots for smartphones and a pair of strategically placed USB-C ports.

The rear door bins can take one large bottle each, while a fold-down central armrest is also on hand, featuring a shallow tray and retractable (and flimsy) cupholders.

Alternatively, the $2800 Rear Seat Comfort Package fitted to our test vehicle subs in a tablet that can control the multimedia system, a wireless smartphone charger and a small cubby into the former, as well as a heated/cooled cupholder atop the rear of the centre console.

In the third row, it’s not quite as roomy if you’re an adult. With the middle bench in its most accommodating position, my knees still brush up against its backrest, which is to be expected given it’s primarily designed for children. I also have an inch of headroom there.

Nonetheless, getting in and out of the third row is relatively easy as the power-operated middle bench tumbles forward and provides just enough space to make entry and exit somewhat graceful.

When seated, rear occupants are treated to two USB-C ports and one small cupholder each, so they’re arguably taken better care of than those in the middle.

Child seats are well and truly accommodated, with four ISOFIX and five top-tether anchorage points fitted across the second and third rows, although the latter will inevitably prove to be a much tighter fit.

The driver and front passenger are still taken care of, with a front cubby taken up by two heated/cooled cupholders, a wireless smartphone charger, two USB-C ports and a 12V power outlet, while their door bins take one large and one small bottle each.

In-cabin storage options include the large central storage bin, which hides another USB-C port, while the glovebox is on the smaller side, with about a third of it taken up by the fragrance, which is pumped into the cabin to ensure the interior always smells its best.

For a car that is very much a mid-sized SUV on the outside, the interior can feel a bit too snug, like you’re driving a compact car that’s tried on a suit a few sizes too big (for reference, I’m 175cm tall - above-average height drivers may find the snugness soon turns to claustrophobia). 

While comfortable - it is BMW we’re talking about, after all - there’s not an overly abundant amount of headroom available, a feeling that becomes more pronounced should you shut the big moon roof.

My two children felt slightly too close to “you’re annoying me” distance from one another, which is to say this isn’t really the kind of car you should be getting if you plan on regularly ferrying about passengers in the rear who are bigger than a child. But I really don't think many people with kids would choose the X4 over the X3.

Boot space also takes a hit when compared to the X3 (550 litres versus 525-litres in the X4 - I was surprised the difference wasn't larger - although that expands to 1430-litres with the rear seats folded down. 

The boot opening is also mouth-shaped, which makes packing in wide-load items more of an issue.

Cupholders are plentiful - two in the front, two in the rear, and bottle holders in each door - and there’s a decent-sized storage cubby in between the front two seats. 

The sloped roof, and big fat A pillars, also result in the X4 being a bit more pinched at the rear, which is not especially great for visibility, with the vehicle’s blind spots taking some getting used to.

Cost-wise, the X4 is roughly in the same ballpark as the other cars in this strange sub-segment, but when you add in optional extras - metallic paint, panorama glass sunroof and BMW Laserlight headlights among them - the base price of $95,900 plus on-road costs sneaks up to $101,800, which is is no small figure. 

It’s also a considerable $8000 more than the SUV-shaped X3, meaning you’re essentially getting the same car, but with less cabin and boot space, for more money. To be fair, this is just part of a long tradition of the style-conscious buyer being willing to pay more for less, one that the invention of the coupe pretty much invented.

That kind of money also makes exclusions like adaptive cruise control, heated seats and wireless charging a bit of a head-scratcher.

Still, there’s plenty to love, including an M Sport kit that comes standard with the X4 (a suspension/brake package and various styling embellishments), butter-soft Tacora Red Vernasca leather seats (Sport adjustable for the driver and front passenger), 20-inch M light alloy double-spoked wheels, a head-up display, adaptive LED headlights, and an automatic tailgate. 

There’s also a generous high-resolution 12.3-inch control display and digital 12.3-inch instrument display, the former operated by touch or via the rotary iDrive Touch Controller. 

Cable-free Apple CarPlay and Android Auto are also available, but BMW allows you the option to use its iDrive system instead, just in case you're some kind of mad Munich fanboy - or you hate Apple. 

The GLS63 is powered by a familiar 4.0-litre twin-turbo V8 petrol engine, with its version producing a thumping 450kW of power at 5750rpm and 850Nm of torque from 2250-5000rpm.

This unit is mated to a nine-speed torque-converter automatic transmission and AMG’s fully variable 4Matic+ all-wheel-drive system with torque vectoring and a rear limited-slip differential.

This set-up also features Mercedes’ EQ Boost 48V mild-hybrid system, which actually gives a 16kW/250Nm electric boost in short bursts, such as when accelerating off the line.

Speaking of which, the GLS63 sprints from a standstill to 100km/h in just 4.2 seconds, while its top speed is electronically limited to 250km/h.
 

Now, prepare to be confused. In the past, the 3.0 in the xDrive3.0i nomenclature might have led you to believe you'd bought a BMW with a 3.0-litre straight six engine. But in this case, you have not, the 3.0 just means you have a more exciting version of the 2.0; a TwinPower turbo 2.0-litre inline four-cylinder engine, making 179kW and 353Nm that the xDrive system delivers to all four wheels. 

The claimed zero to 100km/h time of 4.9 seconds feels completely realistic as this engine has plenty of poke. Put it in the Sport setting and you'll get some serious shove. Indeed, the switch between Comfort and Sport is very noticeable and changes the character of the car entirely.

The transmission is an eight-speed conventional torque converter automatic gearbox that’s both smooth and responsive. 

The GLS63’s fuel consumption on the combined-cycle test (ADR 81/02) is 13.0L per 100km, while its carbon dioxide emissions are 296 grams per km. All things considered, both claims are unsurprisingly high.

In our real-world testing, we averaged a fearsome 18.5L/100km over 65km of driving, split between highways and country roads, so not your usual mix. A very heavy right foot definitely influenced that result, but don’t expect to do too much better in a normal run.

For reference, the GLS63’s 90L fuel tank can be filled up with 98RON petrol at a minimum.

The X4’s 65-litre tank needs to be 95-octane at a minimum, and BMW’s claimed combined fuel consumption is 7.9 litres per 100km. The temptation to use its rorty little engine is going to push you higher, though - you chose the one with the 3.0 badge on it after all - and we averaged 10.9 litres per 100km in our week together, which was mainly city driving, to be fair. 

Frankly, the GLS63 has absolutely no right being as capable as it is. It’s a really big bus that’s legitimately convinced it’s a sports car half its size.

Being a GLS variant, the GLS63 has independent suspension consisting of four-link front and multi-link rear axles with air springs and adaptive dampers, but its party trick is the addition of active anti-roll bars.

In what feels like magic, the GLS63 is simply not intimidated by corners, despite having massive dimensions and a considerable 2555kg (kerb weight) to deal with.

The active anti-roll bars make the GLS63 so much easier to drive fast through the twisty stuff, almost eliminating body roll, taking one key variable out of the equation for the driver. Active engine mounts are also fitted, helping to settle things even further.

The electric power steering on hand is also good. It is speed-sensitive and has a variable ratio, which basically makes the set-up more direct when it needs to be. It’s typically light in hand, too, until one of the sportier drive modes is engaged and extra heft is added.

So, handling is scarcely believable, which means the ride must be compromised, right? Yes and no. With the adaptive dampers in their softest setting, the GLS63 is very compliant. In fact, we’d say it feels luxurious when compared to other high-performance SUVs.

That said, our test vehicle was fitted with the optional 23-inch alloy wheels ($3900), which look the part but expose sharp edges and other road imperfections, not to mention generate noise easily heard inside. Naturally, feedback is exacerbated in the sportier drive modes.

Anyway, there’s more performance, and the GLS63 has the rest in spades. Its engine is a powerhouse in every sense of the word. It’s so powerful, in fact, that it hilariously hunkers down off the line or when suddenly accelerating at low speed.

Thanks to the mild-hybrid system, wads of torque is available from the get-go, making for a highly responsive driving experience, even in those rare moments when the engine isn’t on song.

While not as characterful as some of the other members in the 63 series, the GLS63 still makes some thoroughly entertaining noises, with its sports exhaust system popping like mad while on the overrun.

All of this ability is very well and good, but you need to be able to pull up quickly, and the high-performance braking package (400mm front and 370mm rear discs with six-piston fixed callipers and single-pot floating stoppers respectively) mercifully does exactly that.

The impressive trick that BMW continually pulls off with its SUVs is giving them the same sensual, muscular steering as its sedans, and an impressively similar ride and handling balance.

The steering is the highlight here, but it's also noticeable how planted to the road it feels.

The X4 speaks to its looks, in fact, by feeling sportier and more alive to drive than you'd expect an X3 to be.  

This is less an SUV for soccer mums and dads, and more a bastard love-child that’s into loud leather and bright neon - a CEO who dressed punk rock-lite on weekends, if you will. 

If those weekends are bereft of child taxiing and loading up the boot with several tons of kid stuff, then you’ll have a blast in the X4. 

A 2018 test gave the X4 a five-star ANCAP safety rating, and an easily located button on the dash brings up the vehicle’s safety suite if you’re the kind of driver who likes to make a few adjustments. 

A 360-degree camera offers multiple viewpoints and is a godsend when parking the X4, since the cabin makes the car feel smaller than it actually is on the outside, and the range of safety features on offer are more than adequate. 

Those include autonomous emergency braking, dynamic braking lights, dynamic stability and traction control, rear-cross traffic alert, speed limit information and hill descent control. 

As with all Mercedes-AMG models, the GLS63 comes with a five-year/unlimited-kilometre warranty, which currently sets the standard for the premium market. It also comes with five years of roadside assistance.

The GLS63’s service intervals are relatively long, at every 12 months or 20,000km (whichever comes first). Better yet, it’s available with a five-year/100,000km capped-price servicing plan, but it costs $4450.

Despite all the brouhaha about other car manufacturers offering more generous warranty periods - seven years for Kia, for example - BMW has not shifted its stance, still offering its standard three-year unlimited-kilometre warranty. Frankly, it's just not good enough.

BMW also offer a Service Inclusive package for $2010 that covers owners for five years, or 80,000km.