I don't have a Mini Metro, but I have a Citizen. For me, the Citizen is the right size. On a typical day, I'll have a lock, a 13" MBP, a fat textbook or two, a few folders + notebooks, and little things like pens and a calculator. If I'm carrying two textbooks, the bag is stretched filled pretty comfortably. When I compared my Citizen to my sister's Mini Metro, I could tell just by looking at it that the Mini Metro was way too small for what I carry on a daily basis. I also think it's nice to have the extra capacity to carry awkward packages like boxes or baking pans or something. Like hamish5178 said, the bag is not comfortable for long distances coupled with heavy loads while walking, but I find it very comfortable when I'm riding.