Have owned about an equal number of both however the O/U's largest caliber was 9.3x74R, SS 470NE. I find I SHOOT the O/U better than the SS. Have no idea why, I just do better offhand AND from bench with O/U. Maybe because all my shotguns are O/U's however i'm just a mediocre shotgun shot. I find it easier to mount a scope on the O/U and I do like to use a scope. Most O/U's i've seen the regulation problems are easier and USUALLY you only have to deal with vertical dispersion rather than horizontal AND vertical.