I had a 190D 2.5 5 speed for about 5 years and 120K miles. It was pretty trouble free. I've heard lots of bad things about the 190 series but I've had very good experiences with them.

The 5 speed Diesels (2.2 and 2.5) could exceed 40MPG on the highway. I have not driven a newer VW TDI but the mid 80's Benz Diesels were far superior to the VW's of the day.