All depends on your distance and what type of style of shooting, over dekes, in timber, passing. I mainly hunt over dekes in either field and boat. I shoot Super X2's with Briley Ext. modified in early season and then go to Imp. Mod a bit later.
I shoot Kent 3"-2's early and the 3rd shot is a 3"-BB. I rarely shoot wood ducks for we just don't get them that much where we hunt. Later in season when the northern mallards are starting to get here, I switch over to Hevi-Metal 3" 2's. Costly yes, cripples no.