The Audi has the issue of being tightly linked with VW. I used to love earlier Rabbits and Golfs, but got seriously burned by a 95 GTI with the VR6. Literally. The thing eventually burned to the ground from an electrical fire. I also had cooling issues with that engine. Now, my problems were all with the Mexican assembled cars, so it may not apply to the German ones. Still, I would look carefully at the reliability data.
So far my Audi (2010 Q5) has been great, but it has only been a few months. I had 2007 GTI which was full of issues over the course of 2 years, namely:-
-faulty brakes. About one week after buying it (new) I complained that the brakes were too soft, apparently there was an issue with the brake master cylinder and it needed to be replaced.
-above brake issue was never resolved to my satisfaction, I had no confidence in the brakes. They were still very soft, and the pedal would go all the way to the floor with little effort from me.
-excessive noise when driving, I suspect it had to do with grinding from the brakes. The dealer blamed the bridgestone tires (Which came stock). Basically I would hear like a whirring noise which literally drove me crazy, it was more pronounced when braking/slowing down.
- A/C broke down on me twice
- battery died
Otherwise, it was pretty decent as far as handling and shifting (via DSG). Fed up with the issues, I traded it in for a 2009 Mini Cooper S which I love.
And totally unrelated to the car itself, but someone busted my window to steal some sh*t. I took it to VW to repair, they did do.....they wanted like $100 to vacuum the glass, I told them I would have someone else do it for cheaper.