Volkswagen is very quick to point out that the earlier transmission woes with its DSG gearbox have been fixed. Certainly, the later versions seem to be better, but the jury is still out on whether the fix has been a complete one.
In any case, that’s no use to you as the cars made around 2010 are, indeed, the ones that were most affected by these troublesome transmissions. The smaller Audi models were the main offenders as some of those used the dry-clutch version of the DSG. The larger (and heavier) A4 tended to have the wet-clutch version of the same gearbox which wasn’t nearly as problematic. So that should be your golden rule here if you decide to take the plunge: Only buy a second-hand Audi with a wet-clutch DSG. Even then, we can’t guarantee that it will be all sweetness and light, but at least you’re a chance to side-step major problems. Audi actually recalled many of its models to deal with these gearbox issues at the time.
The other thing to be sure of is that any used Audi you buy has a complete service history with no gaps or late services. These cars use high-tech engines that absolutely require clean oil and filters at regular intervals. A neglected Audi is a very good chance to be a pain in the wallet down the track. Like many second-hand prestige cars, these Audis are often cheap for a reason.