Update - I've been using Slacker for a couple of weeks now. I have to say I am impressed with the functionality. I get way more than I ever did with Napster for the same $10 per month. Content seems to be good so far. The UI is a bit confusing at 1st, but as with anything, once you figure it out it's ok. What really impressed me is the ability to cache radio stations or playlists onto my blackberry. You can do this over WiFi so when you're travelling and not in wifi range you can listen to the locally cached songs. I thought that was really cool. I have been on a Porcupine Tree kick for a few weeks and have built a radio station centered around them and discovering other similar style artists. I was really happy to cache this discovery of music and listen in my hotel room last night without incurring any extra data costs. So far this is looking like a keeper.
