Valeo radiator, MAFF, rust particularly around wheel arches and door bottoms. The C270 has plenty of grunt but gives decent MPG - I regularly see 45+ from my 2001 W203 estate. Personally, I think Elegance has enough toys but Avantgarde has too many potentially expensive to repair electric toys - steering wheel adjust, seat stuff etc.
We've had ours 2 1/2 years now and are really happy with it.