Remote locking failed. Apparently a common fault, being affected by mobile telephones. Required firmware upgrade and 2 days off the road.
Auto-opening boot unreliable. Dealer unable to fault.
Squeak from driver's seat.
Nearside headlamp badly affected by condensation. Renewed under warranty.
It's not all bad. The engine is phenomenal - it will pull strongly in 6th gear and returns tolerably good economy. The boot is huge. The interior light package is very nice. The Bose stereo is good. People admire it, and it's not a BMW.
On the down side, the climate control is unconvincing - never really seeming to do very much about significant discrepancies between external and internal temperature.
There is no MP3 or DAB stereo option (Vorsprung Durch Techik, anyone?).
There are more (i.e., some) cockpit squeaks and rattles than I'd have expected from Audi. I HATE squeaks and rattles in a car. And the interior design is rather sombre (black and silver), although I acknowledge that this is a matter of personal taste.
Most annoyingly, my dealer tends to return the car saying that it's working perfectly only for a defect to recur, sometimes within minutes. This is very vexing indeed. My A4 has been off the road for, I think, 5 days in the first year of ownership for warranty attention to relatively minor faults, many of which have recurred.
In summary, I miss my Alfa Romeo 147. The dealers were no better than Audi, but there was more of a sense of joy about the car. If only I'd been able to put the A4 engine in it...
Update from author of original review -
The car spent yet another day at the dealer this week having the reason for the "Air Bag" warning light being illuminated investigated and rectified: it turned out to be a faulty connection under the passenger seat, apparently. Despite asking for the car to be ready for 16:00, it was 17:50 before I was handed the keys.