Well, IMHO, 3 1/2 shells: More shot, more kick, more price. 3 in. shells, not as much kick, cheaper, shell for shell and IMHO, only very experienced long range shooters can benefit with 3 1/2 shells. Hell, get a Rem 10 gauge, and a 10 gauge reloader and really have fun. That way you can load 1 1/4 oz. for ducks and heavier for geese. I did. And it was FUN watching those mallards fold cleanly.