Diamond reticle is best IMO. Cabelas rebrands one as a guide scope that will work well. Of course, I don't think scopes on shotguns work that well, at least on 12 gauges. I tried a couple and went back to iron sights. Shooting within 100 yards it just doesn't make sense to me.
Plus, recoil is ten times worse with a scope. That is if it doesn't hit you in the face.