Surface seems more like a theme than one particular form factor; but they are pretty radically different in terms of size of course.
It appears to be a solid product judging from the keynote (apart from the demo failure at the beginning).
So far it looks like a replacement for my 1st gen iPad (even 3rd gen, but don't have one heh)
I wonder if they'll have Pixelsense in v2. That is, as far as I know, unique to the Surface table.