Audi A6 with Air suspension ?????????

[ChuckH]

Gents Im in the market for A 3.0 A6 Avant and Ive found a Well speced 3.0 SE 2005 With 27.000 miles at a seemingly very good price BUT it has air suspention ! Now I know nothing at all about this set up ? Is it good or bad ? Do these systems have problems ??
Tame Tech or DrG Your input would be hugely appreciated on this one As TT Im sure You must know the full SP on these set ups And Dr G You opinion on values please ?
Any other inputs and opinions would also be extremely welcome and appreciated!!

THANKS.....................................................