I listen to it sometimes. The selection has expanded a lot since I first started using it so I've been listening to it more often, but sometimes it get obvious that their selection is limited.
But it's neat and I listen to it.
There is a utility that works with firefox that lets you "steal" pandora streamed music, but I don't know much about it since I don't use firefox. But it's out there, and you end up with DRM-free mp3 files...