I was literally one of the first to buy a 2003 C230 coupe and I've loved it ever since. I have to be completely honest here and tell you that its had its fair share of electrical problems. The only problem was the engine was revving at idle just slightly, but this was fixed by replacing the engine controller (paid by warranty) and now it runs smooth as ever. This was the first MB to have the M271 engine and I was expecting some bugs. Other than that I've had the check engine light come on at least a half dozen times, but I've got that taken care of now. I've had no mechanical problems of any kind, no squeaks, rattles or anything like that, just minor electrical problems. Love the car!
Built solid as a rock. Mechanical quality is unmatched. Interior is laid out beautifully. Unique styling (you won't see many on the road). Tons of cargo space when seats are folded down (I love hatchbacks). Affordable for a MB. Not the quickest off the line, but handling is top notch. All glass roof.
Electrical issues need to be ironed out by MB. Engine could be a little stronger at low RPM but what do you expect for such an affordable price, if you want a fast MB you have to pay for it. Transmission could be smoother, but only the pickiest of drivers will notice.