Juno-First put it to the point. Why WP7? Because it's possible. There wasn't an intention by HTC to make it run Android-OS either, but it does, so why not?
In my eyes Android beats WM6.5 in many ways. (What I didn't know, when I was buying my HD2.) So being able to try it, after already buying a phone, really seems like comfort to me...
WP7 hasn't come as far as Android, but it grows and many functions will come along after some time has passed
Nobody forces anyone to play around with different OS, but how many SmartPhone users even get the opportunity?
WP7 is nice, fast and it feels like the HD2 was made for it. That's my stand right now, maybe next week I'll switch back to Android. Who cares? My phone, my choice
Keep it peacefuil by allowing others to choose by themselves.