I've owned my 2010 C250 for nearly 3 years now. Bought it used with 40k kms on it. Good looking car, comfortable and so far very reliable. I've only had to service it and change a few of the lamps /bulbs on the lights so far. I feel the syling has held up over the years. Thankfully Merc don't change their styles too radically.
Only negative would be that the C250 lacks a bit of power when it's needed. Having previously owned a Golf GTI, I missed the power and acceleration on tap.