What also cannot be denied is that others manage to do it. I have many games that work well.
The current radeon + Mesa 10.3-git actually works quite well for many other things. I can't say I've tried everything since the last updates but I'm pretty happy. I did play a few chapters of Metro Last Light without it segfaulting and disappearing. Very smoothly too. I have an impassable point though, where it crashes immediately on loading the next level. Near the end. It's been that way for ages, from fglrx through all iterations of the free radeon drivers and I don't expect it to be any different at this time. We'll see when I get back to that point.
I don't want to buy another Nvidia card, though. They don't seem to last very long. (I've had poor luck with them... the last three I've owned have all died prematurely. One of them spent most of its life in the closet unused too. I used it for several months then shelved it. I sold it with a system and had to replace it a month later.) Also, this new found freedom of being able to build any kernel I want, any damned day I want, without having to contend with rubbish graphics driver module compilation is almost like being back in the good old days.