Haha, I just made a facebook status about this. It's amazing, definitely the best streaming music app I've come across. I just got a 32gb card for my phone though, so I'm debating on if it'll still get much use, but my other laptops will definitely make use of it.
I also love the built in last.fm integration, it was the main reason why I stopped using Amazon mp3,
The Genie function alone is worth using this app for. I like it much better than Genius.