If your shooting competitively I think barrel length combined with fit and balance is a huge issue. Up to a point, sighting plane is a great advantage in a longer barreled gun that also helps in the follow through with one's swing.

However in the turkey woods it isn't that big of a deal. My 28 inch Beretta may even show a slightly better pattern than my 21 inch Benelli but for turkeys the Benelli gets the call everytime (unless I use my New England Firearms single shot). For me at least shorter is more maneuverable in the woods and therefore better. I am not fighting with that longer barrel all day and with tru-glow sights on the shorter barrel there is no problem aquiring the target.