The Unwiredview has published a full review of the HTC Touch Diamond 2, including this video review, around 20 minutes and in two parts, of the device in action.
TheUnwiredview concludes:
Overall I was pleasantly surprised with the quality of my experience with HTC Touch Diamond 2. If you never used a Windows Mobile or HTC device before, it can take few minutes to get used to it.
But HTC is getting really good with full Touch interfaces, and HTC Touch Diamond 2 was a pleasure to play with. Adequate 5 megapixel camera, easy Wi-Fi connectivity and good multimedia performance make this a pretty good choice in mid to high end full touch smartphone category.
Read the full review, which includes many screen shots and example pictures here.