I've gone down the path of the Harmony beta firmware and I am generally happy with the result.
One thing I found though is that my XBMC won't stay asleep. I try to suspend which it does but then within 10 or so seconds it automatically wake again. This never happened before.
I would like to try and compare the Samsung/Panasonic TV approach however I can't seem to be able to map the keys using the GUI anymore. Is there a way to go back to the latest stable firmware again? I've tried but can't seem to get it to work.