Nothing yet!
When I tried the car, I fell in love with it and bought it. I loved the acceleration. It is extremely quick and handle extremely well. I pushed it to the max on the highway and got a maximum speed of 215 km/h or 125 mph.
Even at that speed, the handling was fine. I even drove 14 hours with it, and did not get any back pain and was not even tired. The sound system (6 CDs) is by far the best I have heard so far. The sound is extremely pure.
The air conditionning does a good job at maintaining the temperature even when we had a 36 degrees hot humid summer. Every buttons in the cabin are easy to figure out and are well placed. I did not experience and breakdown yet (touching wood!). I have read in other reviews that there is wind noise coming from the driver's side mirror. I have to admit, there is a noise coming from there, but barely noticeable. Design problem? doesn't bug me anyway. And I love those LED lights!!!
Overall, it is a lovely car to drive, and it is well equipped for a fair price.
More comments to come in 6 months
Update on my initial comments. The car is now at 20000 km (12,000 miles) and is still awesome to drive. I drove a pontiac as a rental for two weeks and it wasn't too bad. Once I got back in my passat, oh my god, the pontiac was suddenly crap. This 07 passat is a jewel to drive. So far, I did not experience any problems with the car, except a airbag light coming on once a week for a couple minutes. I'll get it checked out at the next oil change. Overall, I do not regret my purchase and definitely recommend you to buy one!!!