NONE, there are many advantages to a scope, even at shorter ranges. I suggest you look at John Taylor's book, African Rifles and Cartridges. He wrote this in the infancy of scopes when they were expensive and tempermental at best, and he favored them strongly, not only on moving targets, but stationary ones as well. He writes, "The sole object of mounting a scope is to give better precision in aiming.....I have killed many elephant at ranges between 30 and 60 yards with the aid of scope sights that I'm quite sure I would have not succeeded in killing with any other type of sight...I had to slip my bullet through a tangle of branches and leaves, and the foresight prevented me from seeing what I was doing." A low power scope set on 1.5X allows a very large field of view and allows a much more natural type of shooting in that the crosshairs cover the target without having to align the rear sight with the bead and then position both, in alignment, on the target. Just practice snap shooting at targets with a low power scope and with irons and you will quickly see the scope affords a smoother and more natural presentation in giving a PRECISE shot. Also, if any cats are on the menu, where low light shots are the norm, the scope allows accurate shooting in light where you cannot even see the front sight. Take a low power scope out at night and you'll be amazed how you can still see the crosshairs in very dim light. There are some situations where irons are to be preferred, but the majority of hunting situations on DG are better served by a scope, especially in less experienced hands, not less experienced in shooting, but less experienced in DG hunts. Ask your PH for you upcoming hunt. Betcha he says scope it.