Our home has 4 computers running Windows 8, no hitches (yet). Three of them were upgrades from Windows 7 to Windows 7, the fourth cam with Windows 8 installed. I'm running Windows 8 on a MacBook Pro, thanks to virtualization software from Parallels. At least with Mac OS X I can make my own Image, although it's not well documented by Apple, and have the Image on a USB stick just in case I ever need it. The other two Windows 7 systems were custom-built PCs for gaming, and they had no issues upgrading to Windows 8.