It is surely beta quality (based on an outdated beta driver and it has been announced as beta in http://www.nvnews.net/vbulletin/showthread.php?t=124813
). You miss all the fixes from 180.16
if you use it. Also there might be new bugs in addition to the ones in the "normal" driver.
You will most likely not profit from OpenGL 3.0 at the moment (afaik, there are no games supporting it), but as thunderbird wrote, the new extensions to OpenGL 2.1 might be usefull.
I don't think it does anything to flash performance, but you can give it a try.