Mercedes-AMG G 63 vs Bentley Bentayga V8

Image is everything in the world of ultra-luxurious SUVs and none nails the brief more effectively than the pairing we’ve lined up here. 

The Mercedes G-Class has always been one of the biggest and boldest SUVs, but despite many fairly significant revisions over its life, the first-generation civilian G-Class’s roots went all the way back to the late seventies. So it’s fair to say this military motor-turned-exclusive SUV was due for a refresh. 

That’s what we have here, in Mercedes-AMG G 63 form. While the styling has stayed true to the original, a new engine, chassis and cabin mean this 40-year-old nameplate can cut it with the best and most modern luxury off-roaders in the business.

Bentley joined the fray a few years ago with its first SUV, the Bentayga; and in V8 form, this British behemoth is the Benz’s closest rival, with its similarly high price, strong performance and exclusive image.

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To emerge as winner of this test, one of these cars will have to not only score top marks on each one of those points, but also team its talents in those areas with practicality, technology, comfort and refinement. 

Mercedes-AMG G 63

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A revamp for Mercedes’ flagship G 63 AMG means there’s a new contender in the luxury SUV market. Buyers wanting an off-roader packed with personality and performance should take note – so what’s the £143,370 G 63 like?

Design & engineering

While the styling might not look all that different to its predecessor’s, this new G-Class sports some big changes underneath.

Its body is still separate from the backbone chassis below, which uses independent suspension at the front controlled by three-mode air suspension.

The 4.0-litre bi-turbo V8 is new for this G 63, too, tuned to produce 577bhp and 850Nm of torque. It exhales through the G 63’s trademark – a pair of fat side exhausts – and the prodigious power is sent to all four wheels through a nine-speed automatic box. 

That new engineering means it’s up to 170kg lighter than its predecessor, but at 2,560kg it’s far from a featherweight and still tips the scales at 172kg more than the Bentley. Neither car is light, but you can sense the extra mass in the AMG, exacerbated by the fact that it’s 23cm taller than the Bentayga. 

This means it still possesses all the off-road prowess you’d expect from a G-Class, but these cars will spend most of their time on the road, which is where the overhauled cabin comes in.

It’s familiar Mercedes fare, with a pair of 12.3-inch displays taking care of the infotainment and instruments, and plenty of soft leather. Most of the plastics aren’t out of place in a £143,370 SUV, but some surfaces lower down are disappointing, although at least they feel robust. 

The equipment compares well, because sat-nav, CarPlay and Android Auto, DAB, full-LED lights, adaptive cruise, parking sensors and a reversing camera are included. You also get heated leather seats front and rear, plus metallic paint and modern safety features – as you’d expect at this price.

Driving

No matter how big and heavy the G 63 is, nothing prepares you for how furious it feels at full throttle. AMG’s bi-turbo V8 is a masterpiece and it gives astonishing acceleration. The G 63 romped from 0-60mph in just 3.9 seconds – 0.2 seconds quicker than the Bentley.

Through the gears the cars were evenly matched from 30 to 70mph, with the G 63 stopping the clock in 3.6 seconds and the Bentley taking 3.5 seconds. 

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The gearbox is good, too. In automatic mode, it holds onto gears for just a fraction longer than you might expect, but this at least means the turbos are still on boost and blowing when it shifts up.

Using the steering wheel paddles (real metal and nicer than the plastic paddles in the Bentley) in manual mode, the shifts are sharp enough for a big SUV, with changes announced by a flatulent pop that punctuates the bassy throb from the exhausts.

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Straight-line performance isn’t in question, then. However, the rest of the G 63’s dynamic repertoire is a little more limited, because the chassis is no match for the engine’s incredible performance.

The steering is slow and approximate compared with the Bentley’s, while there’s plenty of roll. You can reduce that lean angle if you switch the  dampers into their stiffest setting, but this disrupts the already lumpy ride still further. 

The car is so big and ponderous that it’s best left in the comfiest setting. Even then, though, it feels like the weight of the body overrules the suspension on undulating roads, floating and wallowing as it rocks from side to side – a legacy of its body-on-frame construction. But big bumps force the axles back hard into the chassis as that live rear axle begins to bind, working through its suspension travel. 

And yet the G 63’s personality is so strong and its character so likeable that you can’t help but forgive its foibles and revel in the talents that make it what it is.

Practicality

The huge body does at least mean practicality isn’t an issue. It’s no surprise that headroom is vast, while legroom in the rear is generous, too – and helped by the fact that you sit upright, which pushes your hips back and stops you slouching with your knees pushed forwards.

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The view out is imperious, while the front of the cabin balances space and comfort nicely.

Storage is good, too; there’s 667 litres of boot space with the rear seats in place (183 litres more than in the Bentayga), plus the load bay is a regular shape and very usable. However, it’s not perfect, because the side-hinged tailgate opens on the ‘wrong’ side for the UK, so access from the kerb is more difficult.

Ownership

In the makers’ chart of our Driver Power 2019 satisfaction survey, Mercedes slipped to 26th out of 30. That’s not great, but much of the tech in the G 63 is shared with other cars in the range that have proven reliable.

It also has plenty of safety tech, so it’ll be safe transport for your family. Autonomous braking with pedestrian detection, adaptive cruise control, blind spot warning and lane keep assist are all included.

Running costs

The result of all that power and weight is that the G 63 is, unsurprisingly, not very efficient. It returned an average of just 17.8mpg on test, which means that, over an annual average of 12,000 miles, it’ll cost £3,773 to fuel. 

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The Bentley was better (just), achieving 20.1mpg in our hands. This means you’ll pay £3,341 at the pumps to fuel the Bentayga over an identical mileage each year. Both will be expensive, then, but given how much these cars cost to buy in the first place, this is likely to be a secondary concern for owners.

Testers' notes

“Despite the new engineering, Mercedes worked hard on the things that make the G-Class what it is. The thunk of the doors, for example, was designed to ape its ancestors. Then there’s the exhaust noise.”

Bentley Bentayga V8 

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The launch of the Bentayga marked a brave move into a new area for Bentley, following demand for a luxury SUV. It’s a divisive car, but you can’t deny its image, which puts this £138,390 Bentayga V8 right in the G 63’s firing line.

Design & engineering

The Bentayga launched with a colossal W12 twin-turbo petrol engine, while a V8 diesel followed later. This was dropped due to Dieselgate, and while you can still get the W12, there’s also this V8 petrol to consider.

It’s a familiar engine from the VW Group (Bentley’s parent company), at 4.0 litres in capacity and bolstered by two turbos, like the G 63’s. However, the Bentley doesn’t quite match the AMG’s output, with 542bhp and 770Nm of torque – but it is lighter.

The Bentayga’s mechanical make-up is also familiar fare; its platform is MLB evo (shared with the Porsche Cayenne), while there’s an eight-speed automatic gearbox and four-wheel drive.

Unlike the G 63’s, the Bentayga’s chassis is a monocoque – so the suspension, transmission and engine are mounted directly to the body rather than having a separate chassis. The Merc’s set-up is good off road, the Bentley’s better for ride and handling.

It’s not often any Bentley, let alone a Bentayga, is dwarfed by its opposition, and while it’s smaller than the Merc, it still feels vast. This means a big cabin packed with equipment, premium materials and luxury. It has the measure of the G 63 on these last two points because most surfaces are covered in leather – and those that aren’t use plusher plastics.

However, the infotainment isn’t as advanced. The eight-inch screen has nav and plenty of other functions, while there’s a digital panel between the analogue dials. You also get heated leather seats, cruise control, good safety tech, a great stereo – all you’d expect from a £140,000 Bentley – and an amazing amount of options to choose from. 

Driving

Despite its looks, the Bentley feels more reserved than the G 63, and that stems partly from its engine. Even in Sport, the V8’s exhaust doesn’t have the gassy bark or the effervescent pops of the G 63; it’s flatter, with a still-deep rumble that signals plenty of performance.

The Bentayga romped from 0-60mph in 4.1 seconds; that’s 0.2 seconds slower than the AMG, but hardly worth complaining about. And the lighter Bentley turned the tables in the higher gears – faster between 50 and 70mph, despite having less power.

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What it also has over the G 63 is handling ability. There is some body roll, but a lot less of it, while it’s combined with faster, more direct steering that makes the most of the extra grip over the AMG.

Cornering speeds are higher and there’s more composure. However, these luxury SUVs are about comfort, too, and the Bentley bludgeons the Merc in this respect. In Comfort mode the dampers control the body better and absorb bumps with a more cushioned feel. In Sport the body control is tauter, but so is the wheel control, which impacts comfort.

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The Bentayga is best in Comfort mode, because it floats fairly serenely in most circumstances. Of course, 22-inch wheels mean the ride isn’t perfect, but these occasions are less frequent than in the G 63.

It inspires more confidence thanks to its better dynamics, and feels lighter, which helps comfort and agility – and is very noticeable under braking.

Practicality

The Bentayga is more than large enough in the rear, and there’s as much legroom as in the G 63. That’s partly because the boot is smaller, but at 484 litres, it’s enough for a family’s luggage.

Instead, here the practicality comes from features such as being able to lower the suspension to make entry and exit easier, a powered tailgate and soft-close doors. Buyers in this market value such luxuries, but there’s still enough space inside the Bentley that carrying people and luggage won’t be an issue. 

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Neither car is that easy to manoeuvre thanks to its sheer size, but the Bentley’s tighter turning circle helps, while 360-degree cameras in both models mean you can judge your parking to perfection. 

Ownership

Unsurprisingly, Bentley didn’t feature in our Driver Power owner satisfaction survey. However, much of its tech is shared with other VW Group brands, so it should be reliable. The car will be safe, too. 

Euro NCAP hasn’t tested the Bentayga, but there’s a good level of tech. Pedestrian detection, cross traffic alert and a 360-degree camera are included in the Touring Specification, while autonomous braking with collision warning, adaptive cruise, blind spot warning and lane keep assist are in the City pack. However, these are optional, at a total of £6,020.

Running costs

Strong V8s in big, heavy bodies mean these will be pricey company cars. Both sit in the top 37 per cent Benefit-in-Kind tax bracket, but the Bentley will be slightly cheaper for higher-rate earners, at a still eye-watering £20,158 a year. The Mercedes costs a little more, at £20,895.

If you’re a private buyer, depreciation will be a bigger factor. Again, both cars are horrendously expensive to run in this respect, with the Bentley retaining a fairly strong 51.9 per cent of its value, according to our experts. This still means you’ll lose a shocking £66,510 over three years/36,000 miles.

The Mercedes works out as only marginally better. It will retain a predicted 55.9 per cent, but is more expensive to buy, so depreciation stands at £63,183. You’ll need deep pockets to run either model, frankly.

Testers’ notes

“Both of our test cars featured acoustic double-glazing to improve refinement, but it’s the Bentley that’s the quieter, more refined car. The noise suppression is excellent, so it’s superbly relaxing.”

Verdict

First place: Bentley Bentayga V8 

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The Bentayga V8 nails its brief as a luxury SUV with an aspirational image. It’s just as quick as the G 63 and pretty much as practical, but its far more sumptuous ride and stronger refinement seal the victory. The tech inside could be better, but it easily has the edge over the G 63 for quality, if not character. That it’s just a little bit cheaper is another win, although that is unlikely to matter to many buyers.

Second place: Mercedes G 63

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This G 63 bristles with character – and more obviously than the Bentayga. Its engine is excellent but it’s not as good to drive. The handling isn’t as sharp, although the ride is more of an issue. It’s also not as luxurious and doesn’t have the same high-quality feel as the Bentayga, even if the tech is more modern. Both will be pricey to run, but buyers will be treated to two of the best, most fun SUVs.

Also consider...

Porsche Cayenne 

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Model: Porsche Cayenne TurboPrice: £101,481 Engine: 4.0-litre twin-turbo V8, 542bhp

The Porsche Cayenne Turbo’s performance matches its rivals’ in this test, because the 542bhp twin-turbo V8 packs a punch. It has a massive boot, too, so it’s on par for practicality, but its image might not be in the same league as these two.

Range Rover Sport 

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Model: Range Rover Sport SVR  Price: £101,210 Engine: 5.0-litre supercharged V8, 567bhp

A 567bhp 5.0-litre supercharged V8 means the SVR has just as much character from its powertrain as the G 63. It rides better and is cheaper, too – which is good, because it’ll leave you more money for running costs; this Range Rover is thirsty.

Figures