The Engaget video (
http://www.engadget.com/2010/10/26/n...irst-hands-on/ ) shows some concerning issues regarding the responsiveness of the touch screen. Might be down to the screen itself, relatively weak hardware or poorly-optimised firmware.
If they don't sort this issue before release it will kill the fun of using a modern tablet device.
There was something odd going on with the refresh rate of the screen, too, although there's a chance that was down to a poor-quality camera being used to film, resulting in 'rolling shutter.'