I've raced a time or two...
I use a Force Grouppo and a mish mash of other stuff.
Is there a performance difference? Don't know but if you look at some of the US Domestic Pro teams (i.e. Jelly Belly, Competitive Cyclist) not all are/were on the top tier (i.e. Force rather than Red).
If I am going to invest the money it is going to go into:
Wheels
Power
Training/Racing

Could really give a rat's ass about whether it is the best of not...