Former (mostly happy until the touch screen died) TP2 user here. I love the Nexus One. I miss the hardware keyboard, obviously, but swype makes up for it.
The unit is incredibly responsive, and now that we have sense ported on the N1 the Exchange integration is excellent.
Now I don't miss the TP2 at all. Especially since I love tinkering with the OS and Android is better than WM for that.