I have a marrekesh with shwalbe marathon plus 700-40's and absolutely love them(very heavy though). also picked up a set of Clement MSO x'plor 700-40's for winter riding here in rural ontario. Road or pavement it doesn't matter, i can go as fast as i need/want to. The Clement tires are light and roll fast at high pressure. I have no issue riding with others to keep up. The shwalbe tires are very heavy but they are very robust, and also at high pressure they roll very well. i have even rode on wood chip paths with them. Will use the Shwalbe's when riding with the panniers. also depending on your physical size, bike loaded or not a larger tire at the right pressure will have a smaller contact patch than a small tire. Less prone to flatting as well. That's my two cents.