The open source drivers for my ATI card are pretty good. Performance isn't spectacular but it's acceptable, and I've not run into any serious bugs for years, and I have no trouble changing resolution at all.
xrandr --output DFP6 --auto --left-of DFP7 --output DFP6 --scale 1.0001x1.0001
I only had this issue with AMD (not Nvidia).
In many ways it's a good thing, I get more code dOne this way.
Is the AMD open source driver better than the closed source one?
For older hardware, the open source driver is getting competitive in terms of performance, and of course has the usual benefits of open source drivers.
TF2 isn't exactly a new game, but neither is my graphics card.