they do look good, especially if you whack on some pimp daddy AMG rims
and they defo aren't as common as some of the other ones you've mentioned, i don't like A3's...but love the S3 lol.
A4's are very nice cars too...i'd go for a diesel though if you do get an A4, they are fantastic with a remap ( 130bhp engines tune to about 170bhp and shedloads of torque

)