I have an original Surface Pro which runs Photoshop and Illustrator fine. The screen on those are to small for any kind of actual design work, but would work fine for showing stuff. I now have a Surface Book which I will take with me when needing to measure things as I will take a picture and write directly on the photo the measurements. I find it to be much better than
paper as I always have the photo for reference. Other than that I never use the pen.
I don't usually show customers anything with it, however if you get one of the higher end ones they will have no problem running your software. I have only had the I7 versions so I cannot comment much on the lower end models. I did have Surface Pro 4 for a while but then returned it to get the Surface Book. Not that I didn't like it, just thought the book would end up being better with a little bit bigger screen and solid keyboard. In my opinion you can't really go wrong with the higher end versions, however they are not cheap.