If it's ultimately between the HD2 and Hero then you ultimately choosing the Operating Systems.
Windows Mobile is old. While it may be the experienced soldier, it is fighting a losing battle..
The HD2 is WM's (windows Mobile) best hope, in Microsoft's battle with it's largest adversaries. Apple and Google.
However, the HD2 has got increadible specs. No doubt.
The Hero has got a refreshing operating system and UI. No doubt.
If you have nothing against WM, and (heaven forbid) like it, take the HD2. Even if it doesn't fit your face.
If you are intruiged by an open system (HTC released the sourcecode, Android SDK available freely) and the apps you could create, then by all means the Hero.
I really, really like both. Alot.
I decided on the Hero for the following;
1) HD2 is awesome. But I hate WM. My friends had WM phones, and they didn't like it either.
2) Though not as powerful, the Hero isn't crippled by WM. I like Android and the Rosie UI.
3) The Hero is cheaper. By alot.
However, since you already had a WM phone, you must like it (I assume).
If you have the cash, go for the HD2.
If you want something different, and cheaper, go for the Hero.
Either way, you won't be disappointed.
