Confused with the Different Mutual Funds Brokers?

I want to invest in mutual funds, since I realized (like an idiot) holding too much cash is a dumb idea, and because several of my last individual stock buys have been stinkers (but overall i'm still on top).

So I was going to invest, but realized there are so many brokers for MFs. Is there a reason why I should pick one over the others? I always hear about Vanguard, and I should select them for mutual funds (from friends), but I don't know what makes them better or special than the others.