All the questions with stability issues around nvidia graphics and unity 3D are closed for some strange reasons which seem to be alibis to me. It seems that nvidia HW was supported well with Ubuntu 11.04 for example (at least for me and many other users) and with 12.04 many many people are complaining NVIDIA support regarding stability at least with older HW. For me the live system of Ubuntu 12.10 doesn't even work stable without any requirements with my Toshiba Tecra S5 (NVIDIA Quadro 130 M, e.g. no status bar no launcher, compiz crashes etc.)
I don't see that many closed questions when you look at the overall tag:
Either way, the examples you cite are problems with Nvidia that we have no control over. Crashes and so on should be reported on the bug tracker, not here. This isn't a place to track Nvidia issues, it's a question and answer site!
Maybe to encourage the use of ubuntu developed drivers and discourage use of closed source drivers!? especially in newer flavours (hint: nouveau dependencies) some of the material my opinion is based on is from here http://blogs.valvesoftware.com/linux/steamd-penguins/ .... the rest is from just trying different drivers! Some comments in the blog more than hint at there will be suitable drivers for gaming soon... that do not break unity/compiz/windows mangement (because of nouveau dependencies)...