Costs & verdict
Everyday costs, plus how reliable and safe it is
Costs, insurance groups, MPG and CO2
No Mercedes S-Class is cheap, but the S350d costs significantly less than other variants as a cash buy. All versions except the S580e plug-in hybrid (PHEV) are in the top (37%) company car tax bracket so that's definitely the version to go for if you're lucky enough to have the S-Class on your company car options list.
With its official 63 miles of electric-only range and 18g/km of CO2 emissions, it sits in a much lower benefit-in-kind tax band than the Audi A8 and BMW 7 Series PHEVs. It also has a gobsmacking 353.1mpg figure, although you'll need to charge it up regularly to get close to that.
Move further up the range and you'll add more kit but receive a big invoice in return. By the way, you can't add any individual options to S-Classes any more.

Reliability
Mercedes placed joint 22nd out of the 30 manufacturers included in our 2021 What Car? Reliability Survey. That's some way behind BMW (13th) and a few places behind Audi (18th) but Range Rover manufacturer Land Rover finished in 29th place.
The latest S-Class comes with a three-year/unlimited-mileage warranty and breakdown cover.