A CM can be carried around your neck like a 35, but gets you away from the grain problem pretty well. An RB is closer to a 4x5, but twice the weight of a Crown Graphic. Those things can be real boat anchors. CM's get you away from "should I rotate the back on this shot?" That back rotating question crops up every time you want to take a picture. Phooey on that. But by the time you crop a square C negative, an RB gives you full frame. A sharper, less grainy photo. But a CM can be carried around you neck, or did I say that?