I've got v16 running on my 8.1 with no probs. 8.1 runs nicer than 8.0 imho. Just make sure you haven't installed to "program files". I have installed into a folder on my D: drive called "apps\datacad16".
Once you get the tiles sorted the way you want them rather than the way MS think you should have them, it runs well. Have added 2 shortcuts to the metro and desktop screens - Shutdown and Restart. shutdown -s -f -t 5, and shutdown -r -t 5. Makes it quick and easy to shutdown or restart. Also have loaded VMWare Player and are running winxp, win7, Ubuntu and about to install 32bit win8 to see if I can get some old dos programs running on that.
"Life isn't about dawdling to the grave, arriving safely in an attractive, wrinkle free body, but rather an adventure that ends skidding in sideways, champagne in one hand, strawberries in the other, totally worn out, screaming 'yeehaaa, what a ride!"