[joeblossom]

User interface is huge for me, especially from a mobile app standpoint. In my opinion, Spotify's mobile app is pretty terrible when compared to Rdio's.

Also, I love the "Collection" feature of Rdio which puts the music I like right at my finger tips rather than creating playlists for every artist with Spotify.

Radio is also available with Rdio for an artist, collection, etc.

[ajtaylor]

The Spotify mobile version has many areas of improvement I'd like to see. Among other things I want: 1) the ability to see the track popularity and 2) a "see more" option when searching.