Yeah, I think a lot of people are moving to Spotify. I myself never paid for either but have use both (using someone else's account on Spotify).

Being able to play offline + any song/album + similar artist play mode makes Spotify hands down the better service.

I think Pandora used to have something special with their Music Genome Project recommendation system but I don't think they really rely on it as much anymore as it now seems based off of the likes and other activity other online radio recommendation systems use.

I wish some one would do a open data version of the Music Genome Project that you could hook up to a personal playlist.