The Mercedes C class pretty much has to be bought with an auto box for
resale and to be drivable due to the awkward foot brake in place of
The Mercedes 220D engine is less powerfull and slower as you point out,
but also rather noisey and agricultural. In my opinion this engine has
no place in a compact exec. car.
The Merc. has a silkier ride than the BMW but is not as sharp and fun
to drive or as quiet and refined. Perhaps the Merc. is the nicer car
to look at. Internal space is much the same between the two. The
Merc. is a more expensive and lacks the build quality of older Mercs.
and the current BMW.
I spent my money on an E91 BMW 3 for the entertaining drive, the
refinement and the more powerful and surprisingly (for a diesel) quite
engine. Until the day that an auto box which does not degrade
performance and fuel economy arrives, I will steer clear of them.