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

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.