Aiyaa... if everybody buy BMW, then Audi distributor can close shop le! I find it nice to spot an occasional A4 B8 on the road... less boring mah!
A4 is a more refine car in terms of fittings and door seals and if that's what you are looking for, its still a valid reason to invest in an A4 over E90.
The one feature I admire most in Audi is the Quattro box.. PERIOD! other than that, its just another FWD car. I think an RX8 or even an Miata handles better than a FWD A4 B8..