I also have both MySpace and Facebook.
I like Facebook because it's been helping me communicate with the members of my district better (I'm a District Director for GSS) as well as any other member outside my district that needs me. It's also a lot cleaner looking than Myspace.
I haven't been on MySpace that long but sadly, a few of my exes have tracked me down
But on the flip side I've been able to re-connect with a lot of my old friends from HS.