I have Windows 8.1 and Poser Pro 2014 works fine.  I have limited use of my hands and like Windows 8 because I can easily use it with a touch screen monitor.  Frankly, I think I would hate it if I didn't have touch screen, though.  At least version 8.1 has a Windows button to get back to the start screen so you don't have to use the Windows keyboard button anymore.