I have a free Spotify account. I was listening today to Spotify radio for background via my computerwhile doing some work when I got a pop up ad mentioning that Spotify was now providing free radio to mobile users. "Great!" I thought. I've never been prepared to shell out $10 a month for mobile music, so til now I'd been stuck with Pandora or Slacker, both of whose quality is crap. I'll take a free upgrade to Ogg Vorbis q5 for sure!
With my computer-based Spotify radio still playing, I downloaded Spotify to my iphone and set up the username and password, then went to settings to set the app to "high" quality from the default "normal". That's when I noticed an option I wasn't expecting -- "extreme". Quitting my computer's Spotify and switching my Airport Express from computer over to iphone, I selected the radio tab on the iphone app, saw the radio station I'd literally just been playing (Thelonious Monk "Blue Monk"), and fired it up. The iphone radio picked up literally where the computer radio left off, and there is no doubt in my mind that I was getting 320 kbps equivalent sound. I could hear a sparkle in the high piano notes and a roundness in horns that just wasn't there off of the computer app.
I've heard what others have said hre that only a fraction of Spotify's library is in Ogg Vorbis q9, but given that I'm using this app for free, I'm pretty excited, and I know the song I was listening to is available in q9 because I heard the q5 version just a few seconds earlier and it the difference was clear as day. Heck, I'm excited just to discover there is now an option with better sq than Pandora and Slacker for my iphone. I downloaded the app fully expecting q5, and what I got was q9. It's ironic that the iphone app actually provides higher quality to free users than does the computer app, but hay, I'm not complaining!
If you're debating whether or not paid Spotify is worth the money, I can't answer that for you. For me it isn't, and nor is paid MOG. It's true that MOG provides its free users with 320 audio, but you only get a finite number of plays, and the mobile app requires a paid account. If I had $10 to burn on music per month, I'd absolutely download 10 songs off of iTunes. But if you're looking for a good free option, Spotify radio for iphone is excellent (and I'm guessing for Android too, but I've only used the iphone app).