The only thing people can say about Rdio, is that it has a really good user interface. However, recent studies show that it doesn't have as much music as Spotify, and the quality of the playback is significantly lower than Spotify as well. The real nail in the coffin is that there are really only about 12 people that use Rdio. So, sharing music is great, if you really like the other 11 people, but real music lovers should stick with Spotify.
- Adam Langer