We traded an 03 Passat for the Jetta TDI. No complaints. A pleasure to drive. As it is a small wagon you can't expect a lot of room. The biggest problem that I've had is the smell of diesel fuel on your hands after a fill up. (really, not much of a problem is it?). The biggest problem we have had was the rock that hit the roof. The good news, it missed the windshield but it did put a dent in the roof.
We average 41 mpg per tank, 47 on a trip, sure can't complain about that. We drive for the best mileage which means not trying to touch the front bumper when you push the gas pedal down. I will wind it up on occasion to clear it out, excessive babying it, is not good for it either.
Continually improve quality of VW TDI vehicles: reduce vibrations, diesel noise and emissons. You see displeasure on the face of a lot of people when you pull in at various places and they hear the diesel noise.