I joined MySpace about 2 weeks ago. I went through all of the processes. I searched for people. I requested friends, sent messages, uploaded photos, and so on. Throughout the duration of this time, I did find myself having a little fun, but I made sure to maintain my focus on self-promotion, only with a personal spin there. So far, I have only been impressed with the photo management. It obviously wasn't impressive enough for me to publish anything here though.
Yesterday, I joined Facebook. I didn't do too much then, but I did spend about 4 hours on it today. I once again went through all of the processes. I even created a group for the ODUG. While MySpace only had a single workflow that impressed me, Facebook impressed me all-around. There were a few settings that were not intuitive enough to find quickly, but other than that, the experience was very good.
If someone came to me today and asked me which one they should join, I would overwhelmingly endorse Facebook. The interfaces were intuitive, the workflows were simple and easy, the features were plentiful, and there were ways for you to plug-in existing content from your existing site(s). My only true criticism so far is that I wish the importing and exporting of content were expanded to all features, allowed more than one source to import from, and expand those features to the groups as well.
Great job, Facebook! I am a fan! MySpace... Well, the kids like you.