I think it's great.
UI is better than the iTouch. Ever heard music on a radio that you liked, but you didn't know the song name? The ZuneHD would find the song name for you, then it would allow you to add it to cart. If you're new to the Zune, it will give you 14 days of free music.
The cons are the mspoints, the stuffty web browser (which I'm on now, I think it uses IE6), and the lack of apps. Then again, a music player is meant for music, not gimmicky apps.