I’m sharing a monitor between the WIndows and Mac machines. It’s the same Windows Cinema Display I’ve been using 12 years.
To switch from Windows, the work machine, to the Mac, my personal machine, I have to unplug the display, plug it in again, switch places between the Magic Mouse I use for the Mac and the Logitech trackball I use for Windows. Then I need to press the appropriate button a switch on the multi-device Logitech keyboard.
It’s inconvenient–and that’s a feature. Because none of my personal accounts are logged in to the work machine, the inconvenience keeps me away from Facebook when I should be working!