Used test: Audi A8 vs Mercedes S-Class

The Contenders

Audi A8 50 TDI quattro L

List price when new £73,095
Price today £32,000
Available from 2018-present

The A8 has the refinement and muscle to question the S-Class’s dominance

Mercedes S-Class S350d L AMG Line

List price when new £75,505
Price today £38,000
Available from 2018-present

It's long been the big-barge benchmark, but does the S-Class still deserve the title?

*Price today is based on a 2018 model with average mileage and full service history, correct at time of writing

Call up any chauffeur company, whether it's based in Southampton or San Francisco, and you have a good chance of a Mercedes S-Class turning up at your door. And why wouldn't it? After all, the model is a pillar of the luxury car class, and those in the business of moving people from A to B in serenity and comfort flock to them – as do buyers who want all the opulence for themselves.

It's not the only option, though. Your chauffeur might also turn up in an Audi A8 – the S-Class's long-standing nemesis. The rivals have never been more closely matched than in the generations we're testing here. Both focus obsessively on rich interior quality, cosseting ride comfort and cutting-edge technology.

If you buy either car at four years old, you can save more than (wait for it) £35,000 off their prices new. Our test cars are long-wheelbase models with diesel engines, making them well-suited to whisking passengers around for mile after mile.

If you're a chauffeur looking for an upgrade or a suave saloon aficionado searching for your next purchase, read on to find out which fancy four-door is best.

Driving

Performance, ride, handling, refinement

Both cars’ engines pump out 282bhp and produce the same amount of maximum pulling power at identical points in the rev range. It’s hardly surprising, then, that they accelerate similarly briskly, although Audi’s standard quattro four-wheel drive helped the A8 to get off the mark more effectively on our damp test track.

There isn’t a bad gearbox here. The S-Class’s nine-speed automatic is marginally less hesitant from a standstill, but on the move, both are superbly smooth and quick to respond to manual changes (by pulling paddles behind the steering wheel).

There’s a bigger difference in engine noise: the A8’s diesel sounds more gravelly at idle and makes itself heard more when accelerating, although it’s still a million miles from fractious.

The Mercedes S-Class is the more enjoyable car to drive. Its steering is more naturally weighted and the willingness with which it turns in to corners and keeps its body under control is deeply impressive for such a large car. The A8’s steering is precise but numb, while its four-wheel drive provides better traction in damp corners and more predictable handling.

The most important area of all has to be ride quality – and here the A8 is the more comfortable for both front and rear passengers. Both cars in our test have optional 20in alloy wheels, but the Audi A8 smooths over ruts and potholes with less shimmy through its body in town and remains more settled on the motorway.

Next: What are they like inside? >>

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