2015 Mercedes-Benz S500 Plug-in Hybrid review

The market is filling up with plug-in hybrids that make a lot of sense on paper but whose appeal slowly erodes as you become familiar with their real-world capabilities. The S500 is not one of those cars. It’s as driveable and easy to use as any S-class in the range, but more refined and impressively frugal within its comfort zone.

Once the battery’s flat, in normal mixed-road commuter use, it’ll return around 30-to-the-gallon. Most owners are expected to tackle shorter trips and a greater proportion of city roads than that usage pattern contains, and our test route suggests that doing so could add 50 percent to that real-world return.

The car’s four drive modes allow it to juggle electric and petrol power in ‘hybrid’ mode, to run exclusively on battery power, to maintain the current battery charge level in ‘Save’ mode, or to return the battery to full charge via the combustion engine in ‘Charge’.

The controls are light and undemanding, just as they are in any S-class – designed to be easy to modulate for unerringly smooth progress. The inconsistent pedal response of Mercedes’ lesser hybrids would never do for an S-class, but this one doesn’t suffer with it. There’s pleasing progressiveness to the initial brake pedal travel, and while you can just about hear the petrol engine starting and stopping as you vary your accelerator inputs, the engine response is always predictable.

Having almost 500lb ft available so far below 2000rpm makes a telling contribution to flexibility. You can make supremely laid-back progress in this car without dawdling or holding anyone up, simply because all that torque allows you to slip away from standing so effortlessly.     

Refinement in the car is genuinely outstanding. If anything, the absence of combustion noise just gives you a greater sense of awe about the cabin’s suppression of road and wind noise, barely a whisper of air or rumble of tyres being allowed to disturb the onboard calm. The car’s ride is pillow-soft and quiet, taking the edge off both gentle and sharp intrusions brilliantly.

The S500’s luxurious bubble can be burst if you hurry it – not that you ever feel remotely inclined to. This car’s dynamic brief is about as single-minded as they come: be comfy. It’s wonderful if you drive it with the dignified restraint you’d need to keep a knight of the realm in the back seat from looking up from his iPad. Body control becomes imprecise, and the steering a bit vague, if you try to hustle it too quickly.

On the evidence of a fairly short test drive, and assuming you’re a company car tax payer and a city dweller, definitely yes. 

Expect further coverage and a more detailed verdict before too long. But on face of it, this could be the definitive version of what, for many, is the world’s definitive luxury car.

Apparently uncompromised to drive and to use, it will deliver peerless luxury, fine urban economy and remarkable relative value to a good proportion of heartland S-class buyers who’ve been ill-served by noisy diesels and thirsty petrols for decades.