Like a laptop, both the Surface 2 and the Surface Pro 2 balanced well and didn't slide around on my lap when attached to keyboards. I felt very comfortable typing and had a clear view of the screen.
A setup like this would be very helpful for all those events I've had to cover, including Monday's, where I wasn't able to sit at a table and had to balance my tablet or laptop on my lap while I typed.
For the new versions, Microsoft improved the built-in kickstand used to hold the tablet up like a laptop screen.
It is sturdier and works in two positions, one for sitting on your lap and another for placing on a table. The kickstand on older Surfaces had just one position, for the table.
My only complaint is that the keyboard was just a little bit too big for my lap and didn't have quiet enough space to lay flat. But at 5 foot, 2 inches, I'm small. If you're taller, you shouldn't have a problem.