Different guy different taste...
My bro has new C class and I had e91.. he told me BMW is sh*t and he will never buy it.. Now he says "only Audi" cuz his 2yo C klass has some problems.. (hehe I told him and later u will be for BMW and he replied "NEVER!"
)
I think it's about prefference.
No doubt BMW always used to be an attractive and sporty. Merc symbol of comfort. Audi tried to be somewhere between these.
But time has changed.. everyone tries to be everything.. Still I think BMW is most attractive and sporty feel from these, Merc is "retromodern" (for old guys with memories) and Audi for people who just can decide between BMW or Merc
(imho!)