I think the Windows 8 UI and UX have leapfrogged over Apple. OS X basically has the same UI it did when it was introduced - windows, folders, files, icons. Not much has changed, except they’ve added more gimmicks to sell phones because the iPhone is Apple’s cash cow now.
The Windows 8 UI is a radical departure from what we are used to. I think that’s why it has created so much panic from some circles. People are uncomfortable with change, but in my opinion once users try it and get past the learning curve, they are going to love Windows 8. Apple’s tired old grid with icons will be the one playing catchup.
The constant changes in the Windows UI are the things that piss me off the most about Windows. Whenever I upgrade Windows, I get into the Control Panel and set the UI to the Classic scheme and leave it there. I refuse to spend a moment of my precious time chasing crap around a new UI designed by people who couldn’t get it right the first time, and have made it successively more obscure and confusing since then.
The rule in the computer industry for a successful UI: Design a UI, do some real homework on how to make it work, then stick with it - for as long as possible.
At cisco, we had the command-line UI which was cribbed from the DECsystem-10/20 and TOPS. We designed all manner of GUI network management schemes. Any time we even gently proposed deprecating the command line UI, we had our heads ripped off by customers. The TOPS-style UI works, it works well and it’s scriptable - so we were told again and again by customers carrying pitchforks and torches.