The more important part about the Surface vs the Surface Pro is that the “regular” Surface would only run Windows RT, a tablet version of the Windows OS which SketchUp is not written to use. The difference is as Dan showed, the x86 architecture on a Surface Pro allows the full Windows install which SketchUp can use.
Great news though! Microsoft has ceased production on the RT tablets moving forward, you can ONLY get a Surface PRO 4, so getting a current generation Surface will be the Pro version with proper version of Windows. Several people in the office are using Surface Pro 4 tablets and like them a lot.