I'm distinctly underwhelmed by Rdio. I basically started trying it because of the good Chromecast support, but their recommendations are not particularly good (I listen to a bunch of electronica, and one of the (good) choices it presented me with was a Polish artist; shortly afterwards I got a bunch of 70's Polish pop music, and it took me a day of thumbs down and skipping to get it to stop; similarly, I somehow managed to be subjected to a prolonged assault of Irish folk music where the only connection I've managed to spot was that one of the artists have a couple of track that are somewhat similar to a couple of the track of an artist I like a few other tracks of).
And their mobile app is horrible. The amount of skipping is awful; you'd think they could buffer more. Especially when you have synced tracks that it could use to "fill in". Even though I've synced a number of tracks to my mobile, it skips or fails halfway through even those tracks when my network connection is bad, unless I've marked myself as offline. Add on no ability to play my local music, and I find myself almost certain to switch from Rdio to my local player on my phone within 10-15 minutes.
It's nice for when I'm home, using it via Chromecast, and I pick exactly what I want to play, or have the patience to try to beat its recommendations into submission, but I doubt I'll stay a user very long.