Mercedes GLS SUV

The latest Mercedes GLS is the brand’s flagship, seven-seat SUV. It's incredibly refined and comfortable, offering a limo-like experience, and its enormous size results in the best, most luxurious third-row of any SUV.

The GLS will certainly make the decision more difficult for anyone weighing up a Range Rover, Audi Q7, Volvo XC90 or BMW X7, while the flagship AMG model will rival the opulent Bentley Bentayga. They could be swayed by the Mercedes when the E-Active Body Control option arrives because this clever technology sees the air suspension take on a life of its own. Not only does it react to the road's surface but it can also lean the GLS into corners like a roller coaster, help get it unstuck off-road and use cameras to identify bumps in the road ahead and adjust the suspension accordingly.

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With it fitted, the GLS lives up to its "S-Class of SUVs" billing, transporting passengers in serene comfort. There are six- or seven-seat layouts available, with three rows of two seats or a three-person middle bench. Choose the latter and an optional pack sees the middle seat fold down to create a large armrest, complete with a tablet. Buyers can also specify rear entertainment screens and massaging seats.

Luxury might come first but you could also use the GLS as a posh workhorse, thanks to its enormous boot space and 3,500kg towing capacity. All the seats fold at the push of a button and even with seven occupants there's still 470-litres of luggage space - more than most family hatchbacks offer.

Most buyers will choose the GLS 400d with its 3.0-litre V6 diesel, offering 326bhp, four-wheel drive and a nine-speed automatic. Despite the GLS' size, it gets from 0-62mph in 6.3 seconds, so never feels lacking in power. A relaxed driving style suits the GLS best, and while the BMW X7 with four-wheel-steering feels more agile, the Mercedes is reassuringly stable.

The Mercedes-AMG GLS 63 was added to the line-up in early 2020, and it packs a meteoric 604bhp, making it more powerful than the Range Rover SVR, and not far behind the 641bhp Lamborghini Urus. It’s over two seconds quicker to 62mph than the diesel, and features an array of exclusive styling details - not to mention expensive running costs, with fuel economy of around 22mpg.

Besides the hugely powerful flagship AMG model, only one engine is offered in the GLS, putting it at somewhat of a disadvantage to rivals with various diesel and plug-in hybrid power options. A plug-in hybrid could join the range later; the Mercedes GLE, which is the car the GLS is based on, is offered with a diesel-electric GLE 350 de version.

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The diesel GLS 400d 4MATIC can return up to 30.8mpg, which is reasonable for a vast SUV with a potent engine but nothing to write home about. Meanwhile, CO2 emissions of 242g/km place the GLS firmly into the top tier for BiK banding, making it a pricey proposition for company-car drivers. A Volvo XC90 T8 Twin Engine plug-in hybrid should prove much cheaper to run, qualifying for a mid-range BiK band. Other German rivals also offer better fuel economy, with the diesel Audi Q7 returning up to 41.5mpg, and the BMW X7 managing 33.6mpg.

As you might expect, the running costs for the powerful AMG model are even steeper, with careful driving likely to get you fuel economy of around 22mpg at best. CO2 emissions are also equally high, with the GLS 63 emitting 291g/km, a figure that’s close to some supercars. The 4.0-litre V8 engine is only happy with costlier super-unleaded fuel, but we can’t imagine too many owners will be overly concerned.

Annual road tax will cost £150 but its list price above £40,000 incurs a £320 surcharge in the first five renewal years, bringing the total to £365. Insurance is also likely to be expensive, with the previous model sitting in group 50, despite having less power.

The GLS 400d is fitted with Mercedes' familiar 3.0-litre V6 diesel, serving up a sizeable 325bhp and 700Nm of torque. This means that despite the flagship SUV weighing two-and-a-half tonnes, it still has the brute force to get from 0-62mph in 6.3 seconds and on to an impressive 148mph top speed. With so much pulling power arriving early in the rev range, it's an engine that suits the car.

If you want a more powerful engine, the thundering Mercedes-AMG GLS 63 uses a twin-turbocharged 4.0-litre V8 petrol unit. With 604bhp at your disposal, this seven-seat behemoth can hit 0-62mph in just 4.2 seconds going on to a limited top speed of 155mph. The standard AMG GLS 63 isn’t even the range-topper though - the Night Edition Executive pack removes the speed limiter, so you can hit 174mph on the German Autobahn.

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It's worth waiting for the optional E-Active Body Control suspension to arrive because with it fitted, the car adapts to suit the road conditions. It possesses some remarkable talents; adjusting the ride height of each wheel independently off-road, and leaning the GLS into corners like a high-speed train thanks to its 'Curve' mode. This works well on motorways and fast roads but it can't always keep up on twistier B-roads.

Rivals like the BMW X7 are more engaging but the GLS feels stable no matter the conditions. It could do with the four-wheel-steering of the BMW, though, because the GLS feels less manoeuvrable at lower speeds.

Mercedes describes the GLS as the S-Class of SUVs, and E-Active Body Control plays a big part here because it transforms the ride quality. Using forward-facing cameras and adaptive air suspension, it identifies upcoming bumps and potholes and adjusts the suspension to soak them up. The result is uncanny, getting rid of the occasional thumps and side-to-side rocking motion noticeable with the standard setup.

Based on the same underpinnings as the Mercedes GLE, the GLS also shares its dashboard setup with twin 12.3-inch screens making up its instrument panel and infotainment display. Called 'MBUX', this is one of the best technology suites available in a car but some prospective customers may long for a more unique interior than the more run-of-the-mill and less expensive GLE.

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A major strength of the GLS is in the back two rows. Here is where the GLE's huge size really pays off and the comparison with the S-Class makes the most sense. Buyers can choose either a six- or seven-seat layout, with the former fitted with two individual seats in the middle row. Stick with seven seats and an optional Rear Comfort Package Plus means the centre backrest can be folded down to create a large armrest with a removable tablet. There's also the option of 11.6-inch touchscreens mounted in the backs of the front seats to keep passengers entertained.

There are three versions of the regular GLS available called AMG Line Premium, AMG Line Premium Plus and AMG Line Premium Plus Executive. As you might expect, all three are loaded with kit, including 22-inch alloy wheels, keyless entry, a 360-degree camera, Parktronic, air suspension, a Burmester stereo and head-up display - to mention just a selection. Premium Plus adds black alloy wheels, a Driving Assistance Plus package, climate controlled front seats with massaging, upgraded interior trim and augmented reality sat-nav. Premium Plus Executive gets 23-inch wheels and an even more luxurious interior - particularly for those sat in the back - even the cup holders are heated.

The AMG versions get unique styling upgrades, Nappa leather as standard and exclusive interior bits, while the Night Edition model gets some of the extra tech of the higher-spec GLS trims.

Measuring over 5.2 metres in length, the Mercedes GLS is one of the biggest cars on sale in the UK, and this translates to enormous interior space. In fact, Mercedes says the third row is suitable for passengers of up to six feet four inches tall, not just the kids and small adults normally able to fit in an SUV's third row.

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Even with all seven seats in use, the boot still measures a usable 470 litres, which is 144 litres more than the BMW X7. With five seats in place, there's an 890-litre boot and with all the rear seats electrically folded down this increases to a massive 2,400 litres, making it almost identical to the Land Rover Discovery.

If you have a seriously large caravan or perhaps a boat, or even another car to tow, the GLS is also perfectly suited thanks to its 3,500kg capacity.

The Mercedes GLS appears to be an exquisitely crafted car, with little expense spared in its construction, but owners responding to our 2020 Driver Power survey weren't especially positive about the Mercedes brand as a whole. It only came 28th out of 30 manufacturers, with 16.5% of owners telling us they experienced one or more faults within the first 12 months, with electrics and interior trim problems the most common.

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Safety is less likely to be a concern; Mercedes has had a string of five-star Euro NCAP crash-test results in recent years and fits some of the most advanced safety technology available for any car. As standard the GLS comes with an active bonnet to help protect pedestrians in an impact, a multitude of airbags and a system to warn the driver if they show signs of drowsiness. Autonomous emergency braking, blind-spot warnings and active lane keeping are all standard.