My experience may not be typical, but my "certified" 2002 C320 had lots of issues. I bought it with 32K miles. During the time I had it, the following items were replaced or repaired: new transmission, lower control arms, new steering rack, rear differential re-sealed, motor mounts, window switches, rear control arm spring (was sold to me with a snapped coil spring), various climate control electronic motor flaps, A/C condensor, purge valve, squeaky seats, etc. I also found the materials used inside to be much inferior quality than what should be found on such a car. While the dealers were good about trying to diagnose and correct the problems, it was a very maddening experience, especially as the dealers charge premium money for their cars under their "no haggle" pricing scheme. Also, I found that the paint, especially in the front, chipped and scratched very easily. Overall, I found it was built like a Chrysler. I drove a number of 2006 through 2008 C280 loaner vehicles when they were new. They seemed to be better quality both inside and outside. I now own a 2006 CLK and find it a much better car.

Brian
'06 CLK 500
'85 300SD