...heresay has it that ou's are inherently more accurate than ss's because of the vertical (vs horizontal) movement/flex of the barrels on discharge, and the fact that scope mounts (to the extent so supplied) are attached to the top (vs. barrel) rib...

...to the extent ou's traditionally utilize boxlock actions, ou's may prove to be more robust/reliable than ss's in sidelock form...

...imho, a scoped medium bore is more asthetically pleasing in an ou configuration than an ss configuration...tho a fixed sighted ss double in a traditional big bore calibre is an established art form...