There currently is a lot happening in the music space online, with Spotify delaying their launch in the USA, and Myspace Music possibly moving over to a subscription model. MOG music streaming service only costs $5 per month, which means it could be a great little option away from these other major players.
Search looks to be extremely fast, with intelligent auto-complete. Adding songs from various places in the service is simple (compare to MySpace Music, which is still cumbersome after a year). And users can make the playlists private or public.