igbal,

While I've used them all, at one time or another waterfowling, I still use a SxS. I'm fifty something and, you're right, I started hunting with an Ainsley H. Fox double. Now I own and shoot Parker Brother doubles which, to my way of thinking, are the best of the old American doubles. I still have one of the original run of Remington 870 pumps but keep it do to its history and seldom shoot it.
I really don't think it matters if the barrels are O&U or SxS. Fit and practice are what counts. I'm not much of a clay bird shooter, just never got the bug but put a bunch of Canvasbacks working the set and it's an entirely different matter. Just what you're used to I guess.

Joe