Mercedes-Benz GLS Review

Introduction

For those that feel size is absolutely important, step forward the very large Mercedes-Benz GLS. This is a massive seven-seater SUV designed to offer the most cosetting of experiences; Merc itself calls it ‘the S-Class of SUVs’, in reference to its well-admired limousine saloon. 

The GLS has masses of space and lots of model choices, from fast and swanky to really fast and really swanky. It’s a rival to other big luxury SUVs, including the BMW X7 and the Range Rover, although it’s bigger than both of those. In top spec, it’s even competition for super-luxury cars like the Bentley Bentayga and Rolls-Royce Cullinan.

Review Sections

At a Glance

The S-Class is a luxury limousine that’s been the flagship of the Mercedes range for decades. But with SUVs very much in vogue today, Mercedes wanted a car that would provide the same levels of luxury, comfort and technology for SUV buyers. The GLS is the result, and Mercedes even refers to it as “the S-Class of premium SUVs”. That pretty much sums up what you can expect from this, the largest car that Mercedes makes. 

It’s a seriously huge machine that some might think better suits broad American roads than tight British ones; it’s even made in Mercedes’ US factory in Alabama. But with size comes immense practicality; plenty of space for up to seven, and more than enough luggage space in the boot. 

There’s also a broad choice of vehicles, with several trim levels, a diesel engine for (relative) efficiency or petrol engines in the performance AMG range and the super-luxurious Mercedes-Maybach model. All engines have plenty of welly, and the GLS handles very well for such a big car.

Key Features

Mercedes promotes the GLS through its practicality, luxury and surprisingly impressive driving prowess. Much of its practicality is down to its size. Most models will seat seven, although the posh Mercedes-Maybach versions can be specced with just two large and very comfortable chairs in the back, for ultimate lounging. It’s a genuine seven-seater too; while other models will only squeeze small children into the rearmost seats, adults will be able to get into the back of the GLS. 

In terms of luxury, the GLS’ position in the market means that even the entry-level model is loaded with standard features, from leather upholstery to some of the latest technology to keep drivers and passengers informed and entertained. Highlights include screens and tablets in the back, heated seats all round and high-end sound systems.

Even the standard GLS drives well, but the performance AMG models cram in huge amounts of horsepower too. This gives them acceleration that can match most sports cars, despite their considerable bulk.

Performance & Drive

There are three distinct versions of the GLS to choose from, each with their own engine. If you’re after as much power as you can get, then you’ll be tempted by the GLS 63, which houses under its bonnet a big 4.0-litre V8 with a massive 612 horsepower. This gives it a 0-62mph time of just 4.2 seconds, which is very fast indeed.

Almost as quick, but a bit less raucous, is the Mercedes-Maybach GLS 600 model, which drenchs the GLS in luxurious features and gives it plenty of oomph too. It uses the same petrol V8 engine with a still-very-powerful 557 horsepower.

However, most customers will look to lease the regular GLS, which is called the 400d. This is diesel-powered, which means far better fuel economy than the petrol engines, although it still got lots of effortless grunt, with 330 horsepower from its 3.0-litre six-cylinder engine. There is no all-electric version, and no plug-in hybrid model either – something you will find on potential rivals like the Volvo XC90.

Power isn’t lacking then, but you may not expect the GLS to drive as well as it does. Anything can go fast in a straight line, but getting a two-tonne-plus car with a high centre of gravity to go round corners is much more difficult. It does a remarkably good job, keeping body roll well at bay through the bends. This does come at the slight expense of ride comfort though; it’s certainly not overly firm, but when you market the car in comparison to the S-Class, you expect great things. The GLS is fine, but not that level of exceptional.

There’s also no holding the size of the car. You sit high, so visibility is very good, but you feel every inch of its width on tighter roads. Threading the GLS down a tight country lane can be quite the experience, and on wider B-roads you may find yourself holding your breath when lorries pass in the opposite direction.

Overall however, the GLS is a very impressive car to drive. It’s at its best on the motorway, where you can whisk away the hours with minimal effort and considerable comfort.

Running costs & Emissions

This is a high-end luxury car, and monthly leasing costs are predictably high. Compared to the BMW X7, the GLS is even more expensive, and it’s pricey against the Range Rover too, although the Land Rover only has five seats. We would expect the Bentley Bentayga and Rolls-Royce Cullinan to cost more, although with the levels of hand-crafted opulence they boast, that’s not a surprise.

The lack of electric or plug-in hybrid technology means fuelling isn’t going to be particularly cheap, either. Your best bet for saving pennies at the pumps will be to go for the GLS 400d, which promises up to 32.1mpg, while the GLS 600 and GLS 63 will give you up to 21.1mpg and 22.1mpg respectively. Those are best-case scenarios based on official tests, however, and real-world figures will be lower.

Insurance won’t be cheap either, as all GLSs sit between groups 47 and 50 of 50.

Interior & Technology

When you’re spending big bucks on a luxury car, the interior has to be top notch. And in the GLS, it is, with excellent build quality, great material choice and a very attractive design. If we’re picky, we’d say it’s a bit too similar to other, less expensive models in the Mercedes range, but it’s still a very attractive environment.

The infotainment system is something of a showpiece. It’s called MBUX, and it’s one of the best systems you can get in any car. With two tablet-like screens mounted side by side on the dash, it combines a central touchscreen with a digital driver display behind the steering wheel, in place of traditional dials. You can control its myriad features using the touchscreen, or via a touch pad between the front seats. This makes it much easier to adjust while driving than other touchscreen-only systems. Alternatively, there are controls on the steering wheel and a very impressive voice-control system; just say ‘Hey Mercedes’ and tell the car what you want to do.

Practicality & Boot Space

The space in the GLS is one of its main selling points, and there’s loads of it. Front row and middle row passengers will have plenty of head and leg room, and while it’s not quite so cavernous in the fold-up third row of seats, two adults should still be able to get in without too much issue. That’s a big improvement on most of the GLS’s rivals.

If you have all seven seats in place, then you’ll have 355 litres of boot space; not loads in the grand scheme of things, but again better than most of the competition. Fold the rear-most seats down, and that’ll give you a very spacious 890 litres of room, which is huge. It’s less practical though in the posh Mercedes-Maybach model; the big rear armchairs mean you can’t fold the back seats down, and you get a 465-litre boot as a result.

There are also plenty of general storage areas, with big door pockets, cubby holes and a covered tray under the dash.

Safety

The GLS hasn’t been tested by independent safety organisation Euro NCAP, but the big Merc shares much mechanically with the smaller (but still large) GLE. That scored a maximum five stars when it was tested in 2019, and we suspect the GLS would fare similarly well. All models come loaded with some of the latest safety tech, including a lane-departure warning system and automatic emergency braking, which will intervene if you don’t react to an impending crash.

You can also specify a Driver Assistance pack, which adds extra systems that give limited autonomous driving capabilities on the motorway. You still need to be in control of the car, but it’ll speed up, slow down and change lanes for you. Clever.

All models get front, front side and curtain airbags, as well as a driver’s knee airbag, while higher-spec models also get side backs in the back. A set of i-Size child seat mounting points are included on the two outer second-row seats and on the third-row seats, while Mercedes-Maybach models get Isofix mounting points on the outer rear seats.

Options

First, choose your engine, and then you can pick from a range of trim levels. Choose the standard GLS 400d, and Mercedes will offer you a choice of Night Edition or Night Edition Executive trims. Both are very well kitted out; the Night Edition gives you 22-inch alloy wheels, air suspension, multibeam LED headlights and a panoramic glass sunroof, as well as wood and leather inside and a head-up display. The Night Edition Executive upgrades the wheels to 23 inches, adds heated seats for everyone and gives you a removable tablet computer in the back.

Go for the AMG-powered GLS 63 and you get just one trim option, but as it’s Night Edition Executive it comes with the same toys as above. Well, nearly; the alloy wheels are black, and the brake calipers are painted in a sporty red.

Go for the really fancy Maybach model and you can choose between two versions. The standard car has a different, exclusive design of 23-inch alloy wheel, as well as upgraded suspension, and it adds soft-close doors and a top-quality Burmester sound system. The First Class model adds those individual rear chairs, and folding rear tables for the passengers that use them.

There are also various options in the Maybach range, including various two-tone paint combinations, but they’re eye-wateringly expensive. Other options across the range include an Off-Road package. All GLSs have four-wheel drive, but this adds various technologies to help it on the rough stuff, including a downhill speed regulation system and low-range gearing. However, we can’t see too many people wanting to take their very expensive luxury car onto proper off-road terrain.

Rival Cars

The big rival to the GLS is BMW’s X7, and on paper there’s much to be said for the BMW. It's more affordable to lease, more fun to drive, and less thirsty on fuel. But it doesn’t have the breadth of range that the GLS offers, and while it’s big, it’s not as big as the Merc; if size is important to you, whether for image or practicality, then that could be a deal breaker. Audi’s Q7 is also worth a look, but it also lacks the choice in the range of the Mercedes.

Depending on which model GLS you’re looking at, you might also want to look at super-luxury SUVs like the Bentley Bentayga or Rolls-Royce Cullinan. These offer incredible bespoke options and very impressive engineering, but you’ll pay for the nose for them. If driving ability is important, then the Range Rover Sport might appeal; it’ll seat seven, but in less comfort. There’s also the Porsche Cayenne, which is fantastic to drive but will only house five. At the other end of the spectrum, Volvo’s XC90 is a very capable seven-seater, but while it has a premium feel it’s not as plush as the GLS. Or as spacious inside.

Verdict & Next Steps

There is much to like about the Mercedes GLS. If you’re sold on the concept of a really massive luxury SUV, then it does the job very well. It’s loaded with great features, it’s good to drive and it’s tremendously spacious inside. But there are other choices on the market, and you should consider them closely. 

The BMW X7 in particular is a key rival to look at. It might not be quite as capacious, but it’s better to drive and just as nice inside, as well as being more affordable. However, you have such a range of choices in the GLS that the chances are high that you can find a model to suit your requirements. If you do, we reckon you’ll be very pleased with what you end up with.

Where to next?

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*Score based on Select’s unique meta score analysis, taking into account the UK’s top five leading independent car website reviews of the Mercedes GLS

**Correct as of 13/09/2021. Based on 9 months initial payment, 5,000 miles over a 48 month lease. Initial payment equivalent to 9 monthly payments or £8988.73 Ts and Cs apply. Credit is subject to status.