Colleague just brought one back from the US. Fun to use and really very quick in the apps I was using compared to touch and iphone. The rotation lock is really useful I found this really annoying sometimes on the touch.
I still won't be buying one though. Problem is I still need the flexibility and function of my netbook and this just becomes another gadget that duplicates some of what I can do already at twice the cost. As I first feared, the biggest problem is that it's just not that comfortable to hold for any length of time and is difficult to prop against anthing compared to the convenient angled stand that is the lid of netbook.
Like all Apple products, it boils down to whether the different user experience is worth the money and whether you are prepared tolerate the level of control Apple insist on.