We have a huge variation of the C class models here at work, and the general concensus is as has been said above, defo go for the Diesel models.
The new C class Coupe is far superior to the earlier model, build quality has improved and the interior now feels like a Merc. The Saloon and Estate models are also a good, solid car............ but a C class will always be the poor mans rich car, the E class is what you want