It works wonders. Even more so when I go to college. Don't have someone's number? facebook them. Send a link but don't have someone's email? Facebook them. Organize study sessions. Keep in tough of my friends. It's like e-mail and AIM plus more, all in one. I don't have a problem with it, minus all that random groups and shit that people spend 3 hours of their day "liking" but then again, it don't matter because I don't really deal with it.
Personally, I don't see the big deal with them. If you don't like it, no one is forcing you to use them.