I know we have several horsehair brush users here, and for some reason I feel myself getting a case of SBAD. That might be assuaged by a horse brush - although my new synthetic help the malady, so why would yet another brush? 
However we need some numbers, people!
For the new guys (and everyone really, but new guys are sometimes more afraid to air opinions) - Seriously, reviews are great because it puts all the comments and feelings in one place in logical order. So on any kind of item, not just brushes, if you have something that no one has reviewed yet (or even if they have), don't be afraid to post one! Even if your review conflicts with the majority view - dissenting opinions are sometimes more useful than a big love fest. You don't need to be an expert.

However we need some numbers, people!

For the new guys (and everyone really, but new guys are sometimes more afraid to air opinions) - Seriously, reviews are great because it puts all the comments and feelings in one place in logical order. So on any kind of item, not just brushes, if you have something that no one has reviewed yet (or even if they have), don't be afraid to post one! Even if your review conflicts with the majority view - dissenting opinions are sometimes more useful than a big love fest. You don't need to be an expert.