Ill give ye an overview of my thoughts and opinions with regards the HD2 and WinMo in general later on bud, im just about to make me tea lol. I don't actually own the HD2, I seriously looked into it (along with the Palm Pre, but o2 don't want anyone to have that), but the lack of a keyboard was a downer for me, I ended up with the Touch Pro 2, which runs the exact same software (WinMo 6.5 and HTC Sense), but has a real keyboard and a resistive tiltscreen. HTC Sense is an absolute dream interface, and WinMo 6.5 is solid as a rock, but there is some pitfalls which need explaining in detail.
Other than that, the HD2 has the advantage of a better CPU, more RAM, and is the first WinMo device with a capacitive screen which HTC had to work very hard with Microsoft to get it working correctly as WinMo does not support capacative screens natively (personally, I think they should have stayed with resistive as my TP2 responds just as sensitively as a capacitive but with the obvious accuracy advantage of resistive, even though it doesnt have multi-touch, it has a zoom bar instead, which many people say is better than pinch to zoom).
Will get back to you on this mate.