The integration with SkyDrive, both within Windows and the Office 2013 preview, is excellent, and a more robust experience than running under Windows 8. Most users should have no problems being productive.
I also discovered that Microsoft is pretty serious about using Windows 8 as a platform for "monetization." (I really hate that term.) You're given multiple opportunities to plunk down your money for music, videos, apps, and other virtual goods.
The real problem is that the shopping experience seems a little too in your face. Now we have an idea of why Microsoft is making the upgrade available at such a low cost—the company hopes to make it back in online store sales.
Still, you can ignore most of that, and spend most of your time in the good old Windows desktop if you prefer. Everything is really just a touch or mouse gesture away.
Windows 8, it turns out, is highly usable. The final release is noticeably more responsive with the touchpad and mouse than the prerelease versions. The user interface is easier to navigate than I'd feared, and the whole affair seems to hang together pretty well.
The responsiveness of the UI, down to mouse movements, scrolling and swiping large swaths of UI screen is incredibly smooth, made possible by GPU acceleration of most of the UI elements.
Whether Windows 8 will be a big winner is still an open question. It clearly has improvements over Windows 7, though the two-step to access the Windows desktop will no doubt be off-putting to some users.
A bigger annoyance, to my mind, is just how eagerly Microsoft seems to want to collect your money after you install Windows 8. How users respond to that will be interesting to watch.