The Intuos Pro Small is great for portability if you travel a lot with your laptop. However, the 157mm x 98mm active area is also a small area to work in, especially if you have large hands. You might get cramps from working long hours with the Intuos Pro Small.
I tend to recommend the medium sized Wacom tablets for this reason. The medium’s active area of 224mm x 140mm gives you more room to work with. It’s ergonomically better too, since it allows you to work from your shoulder and elbow. The touch feature is just a luxury. It’s okay if you have it, but you can sculpt just fine without it.
It really boils down to your needs, especially since we’re talking about two tablets from the same manufacturer. If you don’t have much money, buy the cheaper tablet. If you travel a lot, buy the smaller tablet.