The old Windows tablets had 4 main problems:
1) apps not optimized for touch
2) OS not optimized for touch
3) expensive hardware
4) inefficient hardware/small battery life
It seems to me that with devices like Surface Pro, the 1) and 3) problems are still ported to the new devices. I don't see legacy apps that aren't optimized for touch and on a 10" screen, as an "advantage" for Windows tablets. For all practical purposes, they are not.
Even if you want to do "work" with legacy apps when in "laptop mode" - are you sure you want to do that on a 10" screen? Because I'm telling you 10" is too small for productive work, and the keyboard is too crammed at that size.