I'm paying about £170 for a "variable service" at just under two-year intervals. That works out at less than £100 per year on sevicing, which is pretty reasonable overall compared to any other make of car that needs fixed one year services and it keeps an Audi stamp in the book for better resale later.
I accept that you don't need to get it serviced by Audi for the warranty, but mine's out of warranty and it can only help any arguements I get into for out of warranty claims or resale value if I have a full stamped book.
My local VAG specialist was a similar price for each service, every time I checked, so no benefit there.
On top of that, as its my own car - I actually change the longlife oil and filter myself "mid-service".
You used to have to change diesel engined car oil every three months as the soot particles get into the oil, turn it heavy and block the filter.
I accept that oil has come a long way, but the oil in Audi diesel engined cars still gets very black quickly, so there must still be loads of soot getting into it and for £20, changing it at 12-month/10,000 mile intervals seems a good idea to me. 2 years or 20,000 mile intervals must be really pushing it and can't be doing its best for the protection of the engine after all that use....
A new oil filter and a 4.5 litre can of proper 507.00 spec longlife oil cost me just £22 in total from my local Partco motor factors this week and a quick 30 mins under the car saw it changed quite easily....
As I'm paying myself and its my own car, having a proper longlife service every two years getting the book stamped and then doing my own mid-term for the longevity of the car seems a quite economical option and provides the best of both worlds.