I have owned for 2 years and put 55K miles on my A3 TDI.
Bought car for performance and great MPG - commute is 100 miles per day.
With 500 miles left on warranty Mechatronics unit went - first time had issues was 25K miles and dealer did software update. (it's roughly$3,200 repair if out of warranty).
At 54K miles EGR valve clogged with ash - ($800 repair & AUDI offered no help)
I called AudiUSA and got nowhere.
DO NOT BUY this car for MPG savings, you'll give it all back in repairs. Overall nice car but, I also own 2 Toyotas and I'm spoiled by the fact that they don't break...I had always heard that Audi/VW reliability issues were a problem, definitely some buyer's remorse on A3
Handling and performance, 37 MPG average is great
Car should have 100K mile warranty, AC unit doesn't cool car very well, lights should be auto on-off