And unlike Launchcast and Pandora, it really responds to my OCD-like need to control my playlist. Almost too well at the moment since I've just started programming it and am starting to get repeats.
Unfortunately, the free version is a little underpowered: you can only select 100 songs (but as many groups as you like) and you're stuck with ads. So if I'm sticking with it, I definitely need to pay up. The price is $4/month, which is $1 more than I was paying with Launchcast, but not bad at all considering how much I'll use it.
I'm also very intrigued by their portable player, which picks up a bunch of new songs from your playlist anytime it's near wi-fi or plugged into the net, so you can take your customized radio station with you anywhere. That's just genius.
Before I bite that bullet though, I need to give Last.FM another shot.