So, I installed the GM candidate on my late 2016 MacBook Pro (w/460 4GB) and it seemed fine, nice and quick until I ran a couple of games. The performance has taken a hit, probably due to the games not supporting the newer Metal libraries but World of Warcraft took a straight 50% frame rate drop. So, back to Sierra I went. Seemed to take a lot longer than a normal restore due to faffing about with the drive to get it off of APFS but back on Sierra everything is flying again. Will def put High Sierra back on once WoW is updated etc.