Be that PSN is getting subscriptions I think Xbox Live has the far and away superior version. Games on Demand, NetFlix, Zune Marketplace, Arcade, Game Demos, and so much more, for free. The only thing you pay for is to play with other people.
Xbox LIVE is better because you have a very large community and there is so much more you can do with LIVE. PSN is ok, but i really perfer LIVE. It offers more to me when playing with friends and when downloading games or movies or music off LIVE