Intel drivers, lack of horsepower aside, are much better than either nvidia or amd at this point. You do not need to restart X to change resolutions or manage screens, it's just an xrandr command. It works very well.
That said, a lot of games on linux deal extremely poorly with multimon no matter what. They'll usually try to play over all screens with sometimes completely insane geometries.
> Intel drivers, lack of horsepower aside, are much better than either nvidia or amd at this point.
Sadly I have to disagree with you at this point. I used the Intel GPU on my i7 2600k (HD3000) since 2011 on Arch Linux and at some point about six months ago they stopped working properly. On a Displayport connector I didn't get video at all @ boot sometimes, other than by messing with xrandr and unplugging the cable the only solution was to try booting again.
That wasn't too horrible. What was horrible was the fact that OpenGL didn't work at all really. Every time I used anything that utilized OpenGL I would get "GPU hung, stuck in render ring blah blah" in my dmesg every minute or so and indeed the whole GPU and hence the screens would freeze completely for 5 seconds or so. The machine became unusable. No more GPU accelerated mplayer after that (vaapi or any of the opengl options). Google Maps with WebGL was especially hilarious, I only had to drag with the mouse a bit to make the GPU hang.
I tolerated it for a few driver versions but no improvement happened so I bought a passively cooled ATI HD7750 and use that with the open source drivers. KDE compositing doesn't work @ OpenGL 3.1 at all (even though it should based on the driver's specs) and with compositing enabled accelerated video crashes my Xorg so I had to start using Openbox but at least the screen doesn't freeze for 5 seconds at a time all the time.
Really disappointed with Intel, the drivers were extremely solid in the past.
That said, a lot of games on linux deal extremely poorly with multimon no matter what. They'll usually try to play over all screens with sometimes completely insane geometries.