Just to report on experience from my linux box.
Ubuntu 14.04, latest updates
Radeon 6870
intel c2q q9300 (2.5Ghz default; can oc to 3.55 GHz)
8G DDR2-1066 memory
FGLRX 14.301.1001 (14.9) clean install from 14.20 FGLRX
Install went fine, no issues.
Counter Strike Global Offensive - Max performance about the same as 14.20 but stutter when using multicore rendering greatly improved, much more pleasurable experience. Still not at Windows performance or smoothness, but certainly playable. IMO, the game visually looks better in linux than Windows.
Borderlands 2 - Had not tried with 14.20, but I was surprised at how well it performed. Plays choppy at times, but would probably be ok for people who are more casual (console?) gamers. Physx options are not available at all, I'm assuming Physx doesn't have a linux compatible version. Visually the game didn't look as good as the Windows version, just seemed too bright and a little washed out even after tweaking brightness/contrast settings.
No bugs or anything to report so far. Although, if I turn everything to low in CS:GO then people/weapons turn to all black if in any kind of shadow. Doesn't happen when everything is on high, haven't tested to see if the same happens in windows.