For the status of the drivers with your particular card, please see upstream’s compatibility matrix. My experience has been positive; I have been using them for about two months on my dual-head 8600GT (NV50) setup with only a few small issues and a generally superior Gnometris experience.

Some notes:

* If you find bugs (unrelated to the packaging), please report the problem upstream and not in the Debian bug tracker.
* At request of upstream, we are not providing 3D support. Please do not ask for it, as a wontfix tag often offends.
* Bonus points are awarded for removing the non-free nVidia driver; although installation of xserver-xorg-video-nouveau will remove nvidia-glx, purging nvidia-kernel-common and nvidia-kernel-source should remove all the module-assistant generated kernel modules. rms would be proud.