Just got my system upto F 12 today (11.92 actually).
Everything works. The installer played bug free, nouveau is looking good (do i need kmod-nvidia anymore?)
The new network manager interface looks awesome. I noticed some improvement in bluetooth too. Anyway, it’s just been half a day. More features to praise and more bugs to swat as we go on!!
With just a few days left for the final release, I’m sure this one’s going to be an even bigger leap than Leonidas. Go Constantine!!

If you want 3D support, you’ll need kmod-nvidia? nouveau supports only 2D acceleration.
if you’re using nouveau, kmod-nvidia is doing nothing for you. you only need kmod-nvidia to use the NVIDIA proprietary driver. as otherother says, nouveau doesn’t have any 3D support, that’s the biggest thing missing compared to NVIDIA (the other big missing thing is vdpau).
Actually nouveau does have 3D support for newer card families (nv30/40/50 so far), it’s just incomplete:
http://nouveau.freedesktop.org/wiki/FeatureMatrix