This OS might be the biggest Apple flop ever.
There are just way too many fundamental changes which are not proven to be actually better.
I would rather see new iOS touch UI as another full-screen app to see if it can stand on its own before they go all-in with it. Something similar to what Apple did with Classic which was basically another pre-OS X program.
I guess, Apple is being run by different folks today.
The difference is that Windows 8 is an upgrade that will replace older versions entirely. Apple's users who didn't like iOS could stick with Mac OS X, but getting back to old-style Windows from Metro looks tricky (if it can be fully achieved at all). The Classic to OS X transition is a much closer match, except that Apple didn't really attempt to change the way you interacted with the computer at that time (it was/is still basically a WIMP interface).
That's not to say that Microsoft will fail, or that Metro will be worse than the Windows 7 GUI. It's certainly going to be more interesting than the average OS launch, but my gut feeling is that the reaction to this will match the reaction to the Office ribbon.
Assume Windows 8 turns out to be a massive success. Suddenly everyone expects the same apps to run on their tablets and their desktops. Everyone expects to have proper multi-user support on their tablets, full productivity suites on ARM, and the option of buying an ARM laptop with 10+ hours of battery life. They expect these things because Windows 8 proved them possible.
Now what does Apple do? They've bet on single-user tablets, Intel laptops (with better-than-average but still not great) battery life, separate tablet and desktop ecosystems, and tablets that have only basic productivity apps. How do they bridge this gap and pay this debt?
I think Windows 8 is a very nice platform, and though it has some quirks, I think if people try it they will love it. I'm a Microsoft employee, though, so I'm probably biased.
