I was pretty impressed. It's a huge indication that MS is taking the evolution of the computer very seriously and are making a very strong response.
For myself, I'm interested in the device and I may end up buying one, it looks like it could suit my needs very well. However, what's good for me may not be good for MS. I fear that Windows 8 may not be enough of a seamless, hassle-free experience for the average user as the iPad seems to be. If MS only gets the high-end power users in the tablet and PC market I think they have a very real risk of get squeezed out of the market between android, apple, and linux. This is a strong move, and they're still at the top of the market, but the market has been disrupted and they need several strong moves to keep on the top of the game.
