Totally trouble free.
This car has been as reliable as my Honda (no small feat!).
36MPG on the highway at 70 mph.
Quiet, passengers have no idea it is a diesel.
Performance is better than the gasoline version of the same car.
This is the last year with the straight 6 mercedes diesel, as bullet-proof a motor as Mercedes has ever made.
I would never consider buying another Mercedes that wasn't a diesel.