Right, after a few days of touch HD2 ownership, I have a few thoughts:
1) I think the Engadget and Gizmodo review of the device was a little unfair. You rarely come into contact with the normal 6.5 menus thanks to Sense, and when you do the screen is so damn big it makes selecting any of the options pretty easy. Then again, I've had so many windows mobile phones previously that I've gotten used to it and have no particular complaints. I have used the iPhone's OS for a reasonable period of time, and don't find 6.5 to be all that bad in comparison. As for the argument about "the average user", plenty of people I saw/friends and relatives I know in Hong Kong had WM phones, and none of them found the interface particularly hard to grasp.
I'm simply presenting my thoughts/observations here, not starting a flamewar on WM VS OSX mobile VS Android. Each has its merits, and it just comes down to what suits you.
2) This phone is absolutely massive, but because its so thin its actually reasonably easy to lug around all the time. It still fits within my pocket reasonably comfortably, and that gorgeous display makes navigating the phone a joy.
3) The onscreen keyboard is comfortable to type on as a result of the massive screen. I can easily type as quickly on the HD2 as I did on the Milestone's physical keypad. There are, however, some bugs in that occasionally some key presses don't register or just lag.
4) Battery life is reasonably good for such a high specification device. I had wifi on for the whole of yesterday doing some pretty intensive browsing, emailing, etc, and at the end of the day I still has about 40%-ish battery left.
5) The camera seems to be a bit, um, weird in capturing color. I get weird bits of pink on some of the photos, but from searching around the net it seems its a common issue on the HD2 and hopefully a patch will be available soon.
6) Internet browsing in Opera with Multitouch is a joy. I just wish multitouch extended to more applications, but this is not so much HTC's fault as it is Microsoft and 3rd party developers' fault for not supporting it more.
7) The phone is definitely attention grabbing with its sleek metal backplate and pretty "blacked out" front face. I currently have a firm plastic case around it, but just ordered a leather flip case off ebay as I'm worried about the screen (Yes, I already have a screen protector on it) being scratched up or smashed into.
8) There seems to be quiet a bit of support for the HD2 on XDA-developers. Hoping to try some aftermarket roms, and hopefully Android will be ported to it soon for something different
Rumours abound suggest that WM7 will be available officially for the HD2.
More thoughts to come as I continue to enjoy this great device