There's nothing particularly amazing about watching a man try to navigate a system he hasn't been taught how to navigate. Most of these kinds of experiments tend to end the same way, unless the system includes metaphors the users are already well accustomed to using.

I don't think there's any question Microsoft will include an extensive tutorial in Windows 8's final release. If they don't, we can safely laugh at them. As it is, though, this video is rubbish. I could make a similar video filming my Grandmother trying to use Windows 7(She only knows how to use a specific type of Web TV, sans mouse). I guarantee you we'll see similar results.

Windows has a massive install base. One of Microsoft's most important tasks will be to train their current users to make the transition to this new UI. It's not a small feat. But this video completely sidesteps the most important part in the process, and instead asks a man to use a novel, manufactured system with nothing but his natural inclinations. On those grounds, I think he does quite well. But the video is rubbish.