Automatic climate control went wrong 3 times.
Pneumatic/hydraulic suspension went wrong 3 times.
Small electrical failures.
Very nice car to drive, when it's working. Really attracts people at the start. But these failures drive people crazy. It seems MB has gone very far away with the complexity of the car, that even their own dealers cannot fix the problems.
The climate control has gone out few times. Once it was -5 degrees Celsius outside when the climate control failed. We thought we would freeze to death. The dealer could not fix the problem, and time after time it reappeared.
Another non fixable problem is the pneumatic/hydraulic suspension. Time after time the front lifts up and sticks in such a position that you drive like on a horse... This problem also could not be fixed permanently at the dealers.
Every year it has to go to dealership for fixing problems at least 4 times.
Our family has had two C-class. They got attention and boosted our ego, but weren't very good cars. If your ego can stand it, try the Ford Fusion. Ours is just as good a car as the C-class and cost less than half as much. It's 4 years old and nary a problem.
Last week the belt (steering and generator) went out for second time during last two years. Almost had broken my hand trying to steer into the turn...
Now I can choose between Lexus is250 and this MB CLS, most probably will go with Lexus. Much less problems and headaches. Of course it does not have the effect MB does. But always will be waiting for something to go wrong, it's not for me...
PS I drove a lot of different cars (Opel, Audi, Ford), but never had so many problems... It looks that nowadays it's only prestige that is left with the MB badge.