So, I'm posting from Windows 8 right now. So far, my initial impression is that it is interesting. I agree with the Engadget assessment that it still seems disjointed...like two different platforms mated together. I suppose the real test would be to run it on my desktop (as I am now), and also have it running on a tablet, or convertible tablet notebook, and really see how the syncing works.
Something I've noticed thus far, is that the memory usage just seems to keep climbing. I have 6gb of ram on my machine, and as I keep opening applications, the RAM usage just keeps going up. This is interesting, considering that there is no way to "close" the metro apps. I'll have to see how this plays out. I also haven't been able to get the Catalyst software to install correctly to manipulate my triple monitor settings, though Windows does get the job done on it's own reasonably well.
Though, I must say that the way it is now, it seems they took a great desktop/laptop OS (Windows 7), and comprimised it for the touch crowd. Basically, the Metro UI takes the place of the start button and all of it's functionality. With that in mind, I would imagine that it will work wonderfully on a tablet, and add a great deal of functionality currently missing from that form factor. However, for people using desktops and laptops (ya know, the dying form factors </sarcasm>), it just seems a little mixed up and incongruous.
I'll let you know how my opinion changes over the course of using it the rest of the week.