My wife had a 96 C280 with approx 80k miles on it. It was fine except for the Speedometer at 40k. They replaced the whole unit. We never had any other problems with the car. It was still running great when we bought a ML430 to replace it. I gave it to my brother.
My friend has a 91 300E. It looks great as well. Unfortunately at 120k miles it runs a bit rough and the dealer has never been able to fix the problem.