I have both Myspace & Facebook, but I never use Facebook.
I signed up for it because everyone went on & on about how great it was. All it is, is nothing more than a glorified rip off of Myspace. The ONLY thing Myspace did to rip FB off was take the user page & revamp it, which to me, I'm sticking with classic anyways, cause the FB style sucks. (in my opinion)
Furthermore, those groups on FB.. I don't know how great they'd be, I mean.. granted I don't use FB, but what if someone creates a bogus one & plants a virus in it? (Not sure if it could happen, but what if)
SO, in my opinion.. Myspace is it.. barely, & only because Facebook is (to me) a rip off.