well as far as “stable” goes ive been using build 5370 for 3 months. Ive rolled out a couple of hundred windows 8.1 images - all of which are unattended from lan boot -> AD joined “ctrl-alt-del” screen (I use snappydriver via a script on OOBE boot).
I guess later trunk have other fixes but since that build worked for me (and works for me) I have no reason to update yet. I’d give trunk a test in your lab and decide for yourself; it is a world away from 1.2 - if only for the speed increase (not quite double the speed but I’d be surprised if you don’t notice it)