Oooooole!!!
I’m so happy right now! 
I’ll do some tests and post results, probably tonight.
The good:
I’m already seeing a performance boost (~10 fps) by replacing pbuffers (plus different context) with EXT_fbo render-to-rexture.
The bad:
Render-to-depth-texture doesn’t work (e.g. for shadow maps). It also seems that depth rendering is generally not working, at least I can’t make it work here (no depth-testing, strange artifacts, etc). Color rendering (normal render-to-texture) works great though.
And the ugly:
Their pbuffer implementation seems to be more broken than ever (they apparently haven’t worked on it for quite long) and GLSL behaves strangely (the original interface, I haven’t tried GL 2.0’s yet).
That is because this release is probably a leaked alpha version of the drivers.
You got them from here right?
http://www.station-drivers.com/page/nvidia%20forceware.htm
Hopefully, the developer beta is officially coming out soon and the public release is still on for March though… I’d say get active on the NVidia developer forums and post as much info as possible on any bugs though I’m not surprised with defects in a leaked alpha… Still this is very very good news… verify GL20? 
Yeah…