My 16 GB Zune HD is getting here tomorrow.
I have bootcamp (Windows 7), and have no problem using it to download and sync to the Zune. I fooled around with Zune Software 3.0 (4.0 is coming out tomorrow, and from leaked screen shots I've seen, the UI is gorgeous)
Anyone slamming the Zune HD is just a fanboy.
Basically every single preview of the Zune HD has said the UI and responsiveness is better than the Ipod touch, and honestly Apple didn't improve the UI at all.
The Zune UI and interface destroys the iphone/ipod touch in my opinion. You get artist bios, artist photos, and artist backgrounds for every song you have- even if you don't buy it from the Zune store, and the animations look absolutely seamless. A few reviewers have stated the Zune HD was much snappier than the Ipod Touch (2G). The OLED screen looks beautiful too.
I think Zune has a much better system to get album art too, you have full control over it.
The Zune HD will no doubt have a marketplace. They're supposedly going to port over iphone apps. There's a very good chance the app store will be released tomorrow (judging from some of you who say that it won't have any apps- it's apparent you have no idea what you're talking about).