I have shot all sorts of rib styles over the years on both S/S and O/U and can honestly say that they have all made a fleeting difference to my shooting until I get used to the new view but, in the long run, my ability to shoot the gun has been much more to do with the overall fit and the compatibility of the gun's dynamic with my style and type of shooting.
Similar in effect, 'Swamped' S/S ribs attract the same fascination/horror from those not experienced with them but if you are shooting a shotgun properly, you should be unaware of it while taking a shot.
Shooting shotguns (gun down) is all about fit, not rib!
Having said all that, weight and aesthetics are a whole different ball game.
One interesting feature of a Blanch hammergun I am working on for myself is a 'shield' (the small area between the fences that is effectively your rear sight) that is sunk down to the level of the guns swamped rib. This results in seeing a LOT of rib while the gun's PoA is actually quite flat to the target.
This could be considered as an extreme opposite to the Boss rib style. I am looking forward to seeing how this works in practice.
Blanch were very keen on swamped ribs but in all other cases I have seen, have a shield that is approx level with the top of the fences.
