So now an update. I tried nouveau on my computer. I used the latest git from them so it was a bit of hacking and walking around portage to get it working. The end result was ok.
In Nexuiz, lighting (HDR, and all other effects) were just as good with an acceptable fps although it dipped on the popular servers (esk, hoctf), about a bit above 100. However, the one thing that upset me is antialiasing was disabled. Same for xonotic although the fps were unplayable (30). Of course, in "pro" mode (no effects, etc) fps were better and indeed playable, but then no effects doesn't really require much anyway. With the amount of playing around I had to do, at least as I had the nouveau driver, it wasn't worth it.
However, it could simply have been my configs or they ways I do it, they may not have been the best. For example, it makes little sense why antialiasing just didn't work.
In any case, the nouveau driver seems to be showing progress, so I'll keep an eye on it and play around with it from time to time. It's getting there.
And that's great when we talk about FOSS, even though "it's getting there" is usually derogatory phrase in the rest of the software world. The thing is even though nvidia drivers are better, they are closed meaning they won't "go anywhere" from here. Nvidia has already shown they care shit about their linux users anyhow with their dropping of nv. So really, unless nvidia decides to care a bit about us again, nouveau seems like the better hope ^_^
I keep playing around with it and I'll keep you all posted.
bye / bad luck and have boredom