Windows 8 is OK on non-touch hardware, but it really only makes sense with touch hardware. The magic isn't in the start screen, although that is nice with touch, it's really in the browser. It's the simple things like 'swipe down from the top to close an app' and 'swipe to right or left go back or forward'. It's really quick to navigate. Also the ability to have two apps side-by-side in the touch environment is very nice. I can't tell you how many times someone starts a facebook chat with me and I am busy browsing the web ... you can pin the chat to the side (take a quarter of the screen) and do both at once.
Anyway ... You may like windows 8 on your Mac, but it's really a 2nd class experience without touch. Also, touch on an ultrabook makes total sense once you use Windows 8. It doesn't make sense in the desktop nearly as much, but the proper windows 8 apps are really nice. My gf has noticed that I rarely use the trackpad on my touch ultrabook now and got so jealous she just bought a touch Win8 machine.
The other thing about Windows 8 is it feels like it's part of the internet and totally connected. If you use all Apple cloud stuff, you likely won't get that full experience on Windows 8 of course, but you can get the skydrive app for your iPhone or iPad. Anyway ... not trying to convert you because I am sure you have your reasons for choosing Apple, but I hope you enjoy the 920. The software is not perfect yet, but I firmly believe it will be fixed quickly.