Benz's latest luxury SUV is all about the dimensions — and versatility.

Size rather than sumptuousness is the link between the newly renamed Mercedes-Benz GLS and the company's S-Class flagship.

This is a large luxury SUV with hugely impressive refinement in terms of noise and body control but it simply can't match the sedan's benchmark levels of comfort and convenience. Get over that expectation and there's a lot to like about the big Benz.

It will genuinely carry seven adults and still has room for a couple of cases, it rides and goes far better than something this size should and it has a monstrous three-pointed star on the grille to let the world know this is an imposing vehicle.

This is essentially a facelifted version of the GL range, but Mercedes has rebadged all its SUVs to tie them in with their hatch or sedan siblings: GLA to A-Class, GLC to C and so on.

As such, the changes are largely superficial on the outside, though the interior has a few new techno-toys to keep abreast of the competition, including a touchpad on the top of the dial used to control the upgraded multimedia system.

The nine-speed auto helps quell fuel use in most situations but is also more than willing to hang on to a gear when the driver — or drive mode — is in the right setting. Steering is light at city speeds and belies the fact you are piloting a 2.5 tonne machine. The 12.4 metre turning circle isn't going to be a high in tight backstreets but is comparable with an Audi Q7.

On the road

Seven-seat SUVs should not be able to run down road trains with the ease of the GLS 500 CarsGuide tested. The official 100km/h time of 5.3 seconds is eye-opening but the twin-turbo V8's mid-range acceleration when looking to overtake is more impressive still.

Standard gear on the 500 includes heated and cooled front seats, heated second-row pews, a digital TV tuner and a sunroof. The seats are snug and supportive but lack the pillowy headrests found on the S Class. Still, this $162,000 SUV is $100,000 cheaper than an S500, so you can't be too critical.

You can feel the weight wanting to push straight on through the turns.

Accessing the second row of seats is a cinch but it takes a little manoeuvring to slip into the back two seats. Once there, head and legroom is more than reasonable, making the GLS a practical people-mover (as distinct from kiddie carrier) should the need arise.

Benz says the standard GLS has some off-road ability. Those who insist on taking a luxury car into the scrub should option the Off-Road Experience pack which uses the air suspension to help the big SUV traverse serious obstacles. I'm guessing there won't be a huge take-up …

Fuel use is entirely dependent on the driver's right foot. It is possible to come close to the claimed 11.3L/100km consumption — we saw 12.1L — but more aggressive driving on winding roads can push fuel use into the high teens. The GLS 350d is on sale for those who intended to log decent mileage in their SUV and its 3.0-litre diesel turbo uses a claimed 7.6L/100km.

Grip is outstanding in the wet and you'd have to be manic to find the limits on a dry road. You can feel the weight wanting to push straight on through the turns but it is tamed by the suspension and all-wheel drive.

The fit and finish is as you'd expect in a car at this price and it is loaded with active safety software from adaptive cruise control to active blind spot and lane-keeping assist, crosswind compensation, autonomous emergency braking, "intelligent" LED headlamps and auto braking for pedestrians and traffic passing behind the GLS when reversing.

The car hasn't been officially crash-tested yet but five stars is likely.