I used to have a 2005 B6 A4 1.8T quattro. Unlike the popular belief of these cars always breaking down, mine only had one minor problem - a coil pack had to be replaced. Other than that, the thing was a cherry and I never had any other problems with it.
I also have a friend who used to have a 2006 B7 A4 2.0T (fwd) and he never had any problems either... he ran that thing until just over 200k miles and recently got a brand new A6 a couple weeks ago.
In comparison, my e92 (328) is way quicker than the A4 4bangers - which just shows how slow they are without a big turbo upgrade. my e92 handles way better in all conditions... I don't know about the new B8/9 quattro system, but the previous ones still understeered heavily. my e92 looks sexier than the previous A4's. However even being 7yrs old, my B6 interior looked and felt WAY nicer and cleaner than my e92 and even the new F30's - in my opinion.