Pandora does enough for me. And it's free. So I have to listen to a commercial every 5-8 songs...big deal.
I quit using Pandora b/c I found that it played the same songs over...and over...and over again. If you listen to it more than 2 hours, you'll start to hear the same songs repeating.
Spotify is awesome on every level. Apple is making a mistake trying to compete with them.