We like
Unapologetically huge and comfortable, unapologetically fast and cushy, surprisingly enjoyable to drive

Room for improvement
Fuel needle seemingly attached to lead balloon, not exactly fashionable or sophisticated, expensive

Overview

HARMONY is not the first word that comes to mind when reviewing the Mercedes-AMG GLS63. However, the sheer size of this seven-seat upper-large performance SUV could be directly proportional to the amount of criticism it would appear to regularly cop from some talking heads.

Being a 5130mm-long apartment block on wheels made in Tuscaloosa, USA, probably does not help the cause of this flagship GLS. It remains a sitting duck for jibes about it being too expensive, too excessive, too flabby and – again – all in proportion to an unfashionable Super Size Me diet.

Either way, this 2580kg, 5.5-litre twin-turbocharged V8-engined AMG could probably outrun the haters, leaving them in a wake of CO2. Or, perhaps, it could squeeze nasty comments into its boot.

Absorb the above, though, and then be prepared to wipe the cliches clean. There is a good case to be prosecuted for the GLS63 being more efficient than high-end sportscars. Careful not to spill your jumbo-sized fizzy drink.

Price and equipment

Priced from $214,510 plus on-road costs, the GLS63 is self-explanatory expensive. It leaps a whole $70,000 beyond the sensible – by comparison – entry GLS350d with a V6 diesel that slurps 7.7 litres per 100 kilometres on average.

Or less than an outgoing Toyota Camry Altise sedan.

The Mercedes-AMG version also leaps $45,000 ahead of the less-sensible GLS500 with a baby – by comparison – 4.7-litre twin-turbocharged V8 petrol engine. On the upside, there is a heap of standard equipment.

Included are seven seats, with Nappa leather, electrically adjustable front seats with ventilation and heating, the latter of which also extends to the outboard positions of the middle row, plus an electric-fold middle and third row. There is a television up front, along with digital radio, voice control, navigation, Apple CarPlay/Android Auto and 14-speaker, 830W Harman Kardon audio.

There is a panoramic sunroof above, and multi-mode adaptive suspension underneath, between the enormous 21-inch alloy wheels. Plus, automatic reverse-park assistance, blind-spot monitor, active lane-keep assistance, active cruise control, and LED headlights with auto high-beam that can block out particular traffic while keeping the rest of the road flooded with light.

Kitchen sink not included.

Interior

Despite being rebranded from GL-Class to GLS last year, this generation of Mercedes-Benz upper-large SUV is now a half-decade old. In some aspects of its dashboard design and switchgear arrangement, the GLS63 has started to feel its age, though this was never exactly a stylish cabin.

In this day and age of the coupe-style SUV, however, a focus on function over form has become a rare commodity. The Mercedes-AMG is enormously square on the outside because that translates one-to-one inside. Middle row legroom and headroom is vast, and with the Land Rover Discovery 4 now superseded and the Discovery 5 giving up its expansive third row at the altar of more rounded exterior styling, the GLS63 is now the roomiest SUV around for sixth and seventh passengers.

A full-sized adult can comfortably sit in the third-row, and yet there is boot space to spare. The tri-zone climate control even provides air vents right back there – ditched for Disco 5 – plus vents for middle-row passengers on both the B-pillars and lower console.

Mercedes-Benz claims boot space extends 500mm from tailgate to third-row backrest, or 1250mm in length when that furthermost duo of seats are folded, where it delivers cargo volume of 680 litres.

Engine and transmission

Several new generations of sportscars have sacrificed character for the pursuit of improved fuel efficiency. First, naturally aspirated engines gave way to smaller turbocharged units that often surrendered high revability and crisp throttle response. Then, fewer cylinders were used, which often sullied sound.

We are looking at the four-cylinder Porsche 718 Boxster and Cayman here.

The GLS63 is not a sportscar, but it has the engine from one. German-built by hand, the 5.5-litre twin-turbo V8 is gorgeous to listen to, emphatically lathering its 430kW of power and 760Nm of torque all over the tachometer, with response immediately swelling underfoot in spite of its weight.

As a result, the seven-speed automatic does not have to work as hard, though it is brilliantly snappy and reactive in Sport+ mode. The claimed 0-100km/h in 4.6 seconds feels right, and the way this Affalterbach-via-Tuscaloosa big unit raises its nose like a speedboat under acceleration is hilarious.

Around town the trip computer will show beyond 20 litres per 100 kilometres, though, it really is as simple as that. This AMG’s combined-cycle fuel consumption claim is 12.3L/100km, which can be obtained in mixed driving – and, if all seven seats are occupied, it works out to be 1.8L/100km per person. A two-seat sportscar would need to deliver 3.6L/100km to beat it for relative efficiency.

Ride and handling

SUV models that claim Nurburgring lap times – hello Alfa Romeo Stelvio and Porsche Cayenne – have about as much relevance in the real world as a Mars rover does performing a school drop-off.

The GLS63 might wear a Mercedes-AMG badge, but it keeps its sportiness appropriately discreet.

Ride quality is superb, with a wonderful waftiness in Comfort mode only turning marginally firmer in the alternative Sport and Sport+ modes. This is a quiet SUV, despite the huge tyres that measure 295mm-wide all-around.

But if such attributes of refinement are expectations not always exceeded by today’s breed of big, faux-racer family cars, then the big surprise here is the steering and handling of this seven seater.

In short, the former is crisp, quick and beautifully weighted. And in the case of the latter, the dynamics benefit from a broad footprint and enormous grip, allowing a driver to even balance the upper-large SUV on the throttle, patiently and delicately waiting for the weight to shift before allowing the haughty engine to bring home the bacon.

The upshot is that in its own more casual way, this behemoth Benz can absolutely be a pleasure to drive through bends as well as on straights.

Safety and servicing

Nine airbags (including dual front, front-side, rear-side, full-length curtain and driver’s knee protection), ABS, electronic stability control (ESC), around-view camera, blind-spot monitor, lane-keep assistance and autonomous emergency braking (AEB) are all standard.

ANCAP has not tested the Mercedes-Benz GLS.

Mercedes-Benz does not offer a capped-price servicing program.

Verdict

Spend time with the Mercedes-AMG GLS63 and it becomes impossible to hate. Or even dislike. Actually, it develops into being quite likeable, even.

It might tip the scales at 2.5 tonnes, but even compromised coupe-style SUV models nudge a couple of tonnes these days. And most of the more practical SUVs are not as plush, roomy, characterful or comfortable as this particular model.

Anyone who favoured indulgence over sheer space would choose a Range Rover, as it feels more exotic and expensive – if not as extremely fast and expansive – as this Mercedes-AMG. A Porsche Cayenne Turbo could also cancel the need to also have a sportscar in the driveway.

But in some ways the GLS63 merges many broad attributes together. Unfashionable as its styling and economy might be, it is unashamedly enormous inside and express-train fast. For that reason, there is no reason to provide an apology to the haters.

Rivals

Range Rover Autobiography V8 from $257,011 plus on-road costs
Gorgeous cabin bests the Benz, while ride matches it. But for a price…Porsche Cayenne Turbo from $237,500 plus on-road costs
The benchmark through corners, if that really is your thing.