pieis2pi: From what I can tell, the problem comes down to which desktop GUI you are using rather than anything to do with distibution, GPU, or drivers. If you are using a compositing window manager (like gnome) Unity3D doen't use vsync. In order to fix this for Gnome 3, backup and edit

/usr/share/gnome-shell/js/ui/main.js

replacing the line

Meta.enable_unredirect_for_screen(global.screen);

with the line

Meta.disable_unredirect_for_screen(global.screen);

Then, restart Gnome. For me this has completely solved the vsync problem in Wasteland 2 and Pillars of Eternity (and I imagine any other Unity3D game) with no adverse side effects. As a warning, I have read that disabling unredirecting can negatively impact system performance on graphics intensive games, but haven't noticed any problems.