I bought my wife a new C230 Sedan in 2000 and we both love it. The car has 43k miles on it and has been wonderful to own. The engine is not the model of smoothness, but that is really the only drawback to it that I've been able to find in the 2 and a half years we've owned it.
Great gas mileage, the lowest I've seen is 24 hammering on it around town and 28 on a nice highway trip.
Lots of low end torque, (which gets noticeably better with a K&N installed), excellent passing power, etc. etc.
I've also noticed that the engine is very much unaffected by high ambient temperatures unlike my 95 E320, which turns into a slug when outside temps get high. The C230 just pumps out the power on demand whenever you want it no matter what the temps are outside.
If you can get by the general rough sound of the engine at idle, I think you'll love it, I know we do and we don't have any regrets for not buying C280. That engine is smooth but very "soft" on the low end torque issue.