If you are not doing the forging/grinding and heat treatment yourself, very little difference apart from the obvious. There are hundreds of different types of both stainless and carbon steels, some of which make good blades and some of which don't, and it depends how they are treated as well. If it's a reputable company then they should both be good. Do you have a link to the company, or more specific.... er, specifications for the steels they use?
BTW, My personal preference is for carbon, because it 'ages' nicely, is different from the regular knives we all mostly have in our kitchens etc, and I can use it to make my own much more easily that stainless.