If you are going to hunt with it then I would go with a 28" barrel. 28" works well for skeet too and is certainly passable for sporting
s. That said, I shoot sporting
s exclusively and use a 34" O/U ... when people ask I say it is because they don't make a 36"! If the gun is balanced properly then a longer barrel is an advantage on a serious target gun. On a general purpose gun, I don't think it makes much difference ... IMO.