coming from the TP2 myself, I wasnt fond of NoDo. But now that Mango is out, I'm almost positive WP7 will get some spotlight.
The only bugs that drive me nuts is mainly the music player, and how it cuts out whenever you slide the keyboard out. Also, something funny happens to the music whenever you hit the search button. Speaking of, the capacitive buttons are way too sensitive
I hope HTC is working on the fixes, it's a great phone.