I just started using it, and I like it more for the last.fm radio player than the charting stuff. I listen to music all day at work, so my iTunes library on here doesn't mesh with my home computer, where the vast majority of my MP3s are. So my top lists look all weird because a lot of it is stuff played on the radio station.
I LOVE the radio, though. It's awesome. I pretty much every day just have it play artists similar to the Magnetic Fields, and it pulls out amazing stuff! The streaming is great, I've not had a single problem with it buffering or skipping. It's so cool.
Mine is
here.