2x scale is perfect but only OS X gets it right. Windows breaks dragging Windows between average DPI screens and HiDpi screens, Gnome does too except if you use Xrandr to halve your resolution (and patch it to disable the bicubic filter), but then text is rendered at half resolution and it shows. OSX renders almost everything at half resolution, but renders text and GUI elements at full resolution at 2x scale giving the best of both worlds