What I find annoying is that the fps varies so much when playing - I can get over 60fps when flying or looking at open terrain, and then suddenly have the FPS drop to 30 when looking towards some bushes. 30 FPS would be enough for me for the game to feel smooth, but the drop from 60 to 30 makes it seem worse than it actually is. Even worse, the mouse speed seems to vary alot as the FPS goes up/down.
To cure this I made a simple FPS limiter DLL that I use to limit the FPS to 40, playing feels a bit better with it (not a big difference though). The DLL is available
here in case anyone wants to try it, put it to the ArmA2 directory and then add -fpslimit=40 parameter to the shortcut to use.