The best way to use android on HTC HD2 is to copy it on SD, so that you always have the option to come back to window in case of any problem. But it still does not match with the built in android phones. I have experienced android 2.3.4 on HTC HD2.
Converting HD2 to android is a good option to experience android for the first time, but if you want to enjoy the real feel of android, go for a phone with built in android