Engine, 0-60mph and gearbox
The S Class’s engine line-up starts with a 282bhp 2.9-litre straight-six diesel in the S350d. That’s enough to breeze it from 0-62mph in 6.0sec, and it feels every bit as quick in reality. The higher-powered S400d is better still, with an extra 53bhp giving it even more punch off the line. But, regardless of which you choose, it's how effortlessly the S Class builds speed, rather than its outright pace, that is perhaps its greatest asset.
The S450 opens the petrol engine range. It, too, is a straight six, but this time with a 3.0-litre capacity. The S500 uses the same engine but with different tuning for a bit more punch, without any effect on fuel economy or emissions. There’s also an S560e plug-in hybrid, but it’s currently off sale while in the process of being updated for the next model year.
Fancy something quicker? If so, there’s also a choice of 604bhp from the twin-turbocharged V8 in the AMG S63, or a scarcely believable 621bhp in the AMG S65. Needless to say, both provide sports car levels of acceleration. Whatever engine you choose, you will get a nine-speed automatic gearbox that responds well and changes gear smartly.
Suspension and ride comfort
Despite its standard adaptable air suspension, the S Class’s ride quality isn’t quite perfect in every situation. Around town, you can feel the effect of larger imperfections reverberating through to the interior, although to a slightly lesser extent than you would in the 7 Series. But as the speed increases out on the open road, the ride morphs into feeling supremely supple and comfortable. The S Class is easily a match for the very best in the segment in this regard, and considerably better controlled than the Range Rover, which tends to wallow in bends and bounce more perceptibly over dips and crests.
This being an S Class, though, things don’t stop there: depending on which model you choose, there are various options to improve things further still. Magic Body Control, for example, uses a stereo camera mounted in the windscreen to scan the road surface ahead and then pre-emptively adjust the suspension to deal with it. It’s astonishingly effective, to the extent that when travelling over a series of large speed bumps, you’ll barely register their presence.
Then there’s the Curve feature. This leans the S Class in to bends like a motorcycle. The result is less sideways g-forces trying to whip you out of your seat, ergo enhanced comfort.
You don’t necessarily buy a car like the S Class for its B-road agility, yet by this measure the big Mercedes doesn’t disgrace itself. It might not be quite as sharp as the 7 Series, but it offers good body control, especially when firmed up in the Sport mode. You do notice some body lean, though, and the limited bolstering of the seats means you can find yourself sliding around a little in tight corners. But the S Class has better-weighted and more precise steering than the Audi A8 or Range Rover, so despite its bulk, you can stroke it along with relative aplomb.
It’s on the motorway that the S Class really feels at home, though. Even at three-figure speeds on a derestricted German autobahn, it feels resolutely stable, so bumbling down the motorway at 70mph won’t challenge it in the slightest.
Noise and vibration
Even the S350d diesel is smooth and quiet whether you're cruising or pressing on. It's so good, in fact, that it almost matches the ultra-refined nature of the S500 petrol, which is high praise indeed. However; given our experience with the previous version, it seems unlikely that any of these will better the tranquillity of the upcoming hybrid S560e.
The sporty AMG S63 is a direct contrast; its muted V8 burble becoming a full-on bark when you activate the sports exhaust and give it some beans. Switch the S63 to its sportier drive modes and the nine-speed automatic gearbox delivers quicker changes that result in a slight thud in the back. But fear not; if you keep it in the Comfort mode, it’ll shift just as seamlessly as the rest of the slick gearboxes in the S Class line-up.