I know some people who had flashing desktop problems in Windows 10 which make their PC unusable. I think people who experience a flashing desktop problem which make their PC unusable may more likely to dislike Windows 10 more than 8.
I think Windows 8/8.1 is more usable for most users after the user install a third-party startmenu like Start8 program to bring back the startmenu. I didn't have many problems with 8 except the start screen which was kind of a hassle to use on a regular PC or laptop without a touchscreen or motion controls.