I purchased my audi 3.0 FWD two years ago used (had 25K miles on it at the time). I was surprised with the average gas mileage(averaged 26.4 mpg) over the past two years. On the down side, I spent a lot of time in the shop for small items (some covered by warranty). Repairs included new battery, 4 cv boots, head light, two tail lights. On average I spent $1,200 per year in repairs not including oil changes, brakes and tires/rotations. Overall interior quality was less than I expected. The seats showed significant wear, the radio/heating buttons writing wore off and the wood (plastic) cracked during my two years of ownership. I previously owned a saab 9-5 and had none of these problems.
On board computer, size of trunk, sound system.
Better interior quality, more durable seat material