The service seems very nice, something like the Zune Marketplace, I think. You can search for tracks, add them to playlists and listen to them all you want. There is a lot of music, but not everything. I wasn’t able to find many songs from Dave Matthews.

All in all it is another music alternative to have on your computer. With Pandora, Slacker, and Last.fm also to choose from there should be something to listen to all of the time.