I used to use MySpace, but I realized how much of my life was being sucked out of rushing home to check if I had new comments, or a new message, or anything to that matter.
I realized if I wanted to socialize with my friends, I'd rather just talk to them in real life, rather than over the internet.
Only reason i go on myspace is to play mobsters ;p
Facebook is way better for most add-ons, games, friends, profiles, groups etc.
Most my school use facebook, opposed to myspace.. I think most people just use the one which most there friends use.. Which appears to be facebook on the whole.
Facebook, I see that it has more ease, I do like the fact that I get to fiddle around with myspace in html, but the fact that more people have facebook at my school and that its just an ease to check up on them makes me choose it.