Stability- Way too early to tell. Been running them now for about eight or nine hours and no crashes/locks, but that shouldn't be anything to write home about.
Bugs- Some games are not displaying all available resolutions. Not sure what is causing it, but in NFS4 I'm seeing all of my 16bit options but only up to 800x600 under 32bit(should be up to 1920x1440). This is the only game I have seen it on, but I would assume if it pops up in such a popular title it is likely to show up in more.
Occasional shadow corruptions- Not like the problems with some of the other betas, it will display the regular shadow fine, just add some lines going through it.
Performance- Slightly off in OpenGL, heavy on the slightly though Maybe two or three FPS, certainly nothing of any great importance. DX3-7 seems to be nigh identical, no noticeable increases or decreases outside of Sacrifice which seemed to play overall a bit smoother though there were occasional pauses of a second or two(occasional as in once every half hour or so).
DX8, at the very least Giants, seems to be significantly improved. I'm now using 1280x960 32bit everything maxxed and averaging in the 20-30FPS range(if you have Giants you will understand) with my GF DDR and Duron 650. 1024x768 32bit "UHQ" is the setting I was using previously and was seeing low 20FPS pretty much across the board with slowdown on some of the stages(Ripper infestation, base building missions), is now in the 25-35FPS range with peaks in the mid 60s(previously this was mid 40s). For reference, I was able to play through the Ripper Infestation level 1600x1200 32bit everything cranked and made it through first try with about half health left. Definately not a setting I would want to use all the time, but faster then 1280x960 was with the Det 6.50 officials.
Also- the Dot3 rendering seems much sharper now on several of the stages(Dick Whittington Prison for instance), and also things are more contrasted between light and dark(ligted areas are even lighter, areas in the shadows appear a bit darker).
UT with the latest Vogel .dlls is still quite poor under D3D performance wise, though OpenGL now seems to be running very smooth. Not sure what is up with the D3D code, but it seems that the poor performance that everyone has been seeing with it isn't going away with a DX8 driver update. It is playable now, better then before clearly, but with OpenGL running silky smooth D3D performance still seems very poor.
Hmmm, I think that does it for now. I might post back later after I try and run through a few more games for a while.