Currently using Froyo (mattc, RC1.2) on HD2 with exceller dualboot loader (V1.02), working very stable and smooth. Asides the points which have been listed in their posts, I found the following not functioning properly (or just happened to m2??)
1. Every time it reboots, the bluetooth automatically turns on (reported by other users). The HTC bluetooth toggle works funny when I tap it to turn it off- becomes gray but seems refuses to turn off...
2. Can not use google voice search- "process com.google.android voicesearch has stopped unexpectedly-force close". Found some solution in Android Software Development in the forum (just search "voice search"), but I suppose it is only for nand android thus not the solution for our case?
3. The voice in Google navigation is funny, quite robot-ish, any way to change it?
4. My winxp-64bit cannot recognize it as USB storage. Charging with USB cable to PC is fine, but it does not pop-out for selection of functionality, even I manually change it to USB storage. (solved: using different USB port followed by uninstalling the driver in PC device manager, also I installed JRT Auto Mount software listed in market, which might help as well))
Hope this thread is useful, and list your findings here so that our lovely developer can make HD2 perfect.