I've owned mine for three and a half years now. Wonderful machine.
I've had no problems with my DRC suspension, although it is a common issue. I've never had checks for the carbon build up associated with these engines, however the car still feels as powerful and quick as it has ever done (I've driven 45,000 miles in it). It also is as quick as the "on paper" stats suggests - indeed, the Vmax isn't limited to 155, as Audi claim, but 169mph can be reached on the speedo.
The only thing that has caused need for a recovery truck was when my clutch let go.
Normal servicing is every 2 years, 20,000 miles or when the service indicator says it needs it. I've tracked mine and taken it to the continent many times, plus it's usual daily use but my servicing regime has been once a year (approx 16-17,000 miles).
I use it all year, in all conditions. It's fantastic. I've recently switched to Michilen Super Sport tyres over the OEM Pirelli Rossos and upgraded the pads to Pagid RS4-2s. You can really notice the difference and the prices of both upgrades are more or less identical to what Audi charge.
I've only had my car attended to by local dealer. I have heard horror stories about some dealers not knowing how to look after these, but I've had no problems with their service
I would highly recommend going for one, but would offer the usual caution of ensuring you get a decent example with a good warranty.