I think I can make this thread more Nexus 7 related while staying on the topic of your post.
Rdio vs Spotify on the Nexus 7. Which is better?
Well until recently, say March or so, the Rdio app looked much better than Spotify. Spotify was still using android 1.5-1.6 paradigms while Rdio was using 2.3 with a little bit of ICS here and there. But in March spotify looks and feels a lot like the G+ or new YouTube apps. So I kind of like that better. However, Rdio has both 'playlists' and 'collection. What this means I'd you can build a huge library of all the music you like listed alphabetically by artist, and within each artists, listed alphabetically by album, and this only includes what you have added. Spotify can only make playlists. The way Rdio works makes you feel like your using a library of music you spent years collecting, where as spotify feels very much like a streaming service where you have to search and select each song you want to listen to. So for that reason, I prefer the way Rdio works. Also, the developers of Rdio respond to emails and put out bug fixes really quickly once they are reported.