I'm listening to it right now.
Good stuff, if you have the time to mess with it. Took me awhile to get used to it. If you can sit down for a day and plus or minus the songs on the station(s) you like, that will really help things.
The one thing I do not like about it, and why it is free, is that you can't specifically play a song you want at any given moment.
But some very cool things come from Pandora, two thumbs up from me.