I've done 34000 miles in my e300 (it was 9 months old when I bought it with 9k on the clock so has 43k miles in total now). Appart from one odd event it has been entirely fault free. The event in question, hybrid was stuck on amber for entire journey, didn't charge or discharge battery for 45 miles. Then, coming off motorway car completely shut down, all electrics and engine off. Luckily It happened at about 30mph so plenty of force left in braking system for zero drama stop. I've read this has happened to one owner in lane three at 70mph plus. But that was over a year ago and no issues since.
Love the car, gliding silent round car parks is fun. I average just over 51 mpg overall but if I'm a saint I can get get high 60s doing the 53 mile commute to work (a roads and mostly motor way. Best ever was 74mpg over a 60 mile journey but that was drafting lorries the whole way just to see what it could do!
However, now the car is 2.5 years old I'm looking to replace it before merc warranty runs out as I've heard the repair bill if the battery goes can run to 9k!!! That's what I've read early warranty bills were when some people had trouble. Even if it's half that now I'd be quite vary as the electrics only give a mild assistance to the diesel engine but if the battery goes, the car can't be driven.
Hence looking at a new W213 220d which, after a 24 hour demo, also returned a smidge over 50mpg and that was letting the distronic plus so most of the driving (and harsh braking!). I'm sure I could improve that by better forward planning.
If you get a good warranty and like the car id recommend it. I also read recently that the facelift w212 is one of the most reliable cars for its age.
