So does really nobody know the actual differences? I run the 12.9 embedded on my HD 6550M notebook and it seems to work well mostly. I get the watermark and only trackmania nations has major problems, everything else seems to work fine (kde effects, black mesa in wine, etc.).
Still I need to boot with nopat for it to wake up from suspend.
I don't see why AMD shouldn't have two releases for the main driver: One "stable" that is exactly like the one currently and one "unsupported" that gets updated whenever they feel like letting the community test new features or fixes or compatibility with xorg versions... I think in the past the quick feedback from testers would have helped with fixing many things more quickly, or would have prevented faulty "stable" releases altogether. Think, the broken "new" 2d acceleration, gnome 3 "sort of" fixes, etc. It's the bleeding edge users that are used to occassional breakage and reporting things to upstream to get fixed anyway.