rusty, chupa, kilgore, drood and I all use it. its pretty incredible. I have been using it for a couple of years and highly suggest it. The radio feature is highly underrated IMO.
I like the service. My only complaint is the ram usage when not in use. It isn't really a legit complaint because I have to have it running or I would have to add it to winamp start up every time (I have evillyrics set to do this

) and then it might not pick up my first song...blah blah. Really, I'm just an anal retentive bastard who wants to keep my computer running lean. For this reason, I just bought 2 gig of ram this week to add to my box, so I don't think 5 megs will haunt my nightmares so often, anymore.
I too, don't use it to it's full capabilities. I use it occasionally for band information, finding new bands, seeing their most popular song, listening to said song, then getting the album if I like it. I don't really use the radio but probably should.