Technically both together would offer the best stimulation. They hook together and cause constant friction. Though pubes just on the woman would still cause stimulation.

Pubes on just the man would do far less because it's the hairs in the skin(on the woman) being moved that cause movement of the skin in that region. I think it was How To Look Good Naked of all things that clued me into this originally, offering the argument that porn is responsible for it and explaining the sexual side. (Obviously I made sure they weren't full of shit afterwards though.)