I'd have to side with both sides here...
I sometimes hate social sites, especially myspace because of some users putting incredibly ugly styles... not to point out that it gets uber-spammed by comments etc, especially the image ones...
However I also sometimes think it's nice and "feel the need" of them. And to be sincere, the only one that I like is Facebook and maybe Netlog.com (this one is european).. they are nice and clean by design... but a little too complex to do 'casual' use...
Btw, check out some statistics for facebook/myspace..
according to some sources (google them), facebook is used mostly by "the upper class/smarter guys" whereas myspace is mostly(as in 70%) used by the high school drop outs etc... quiete interesting, especially if true..!