While I know some MB fans are just as insecure and become as defensive when other people say $h1t about MBs, I've found more MB enthusiasts who are more willing to accept those comments and just stay happy with what they got.
check out
www.m3forum.com
I think m5board is one of the better ones out there! There are at least more people who can look at other cars and see their merits too!
Don't get me wrong though.
The E39 M5 is one of my dream cars! Along with the W124 500E of course