I think the bungee slings are advantageous because they stretch. Since they stretch they are little easier to manipulate, especially if you have not spent a considerable amount of time training with them or building some kind of muscle memory. The stretching might also be a disadvantage too depending on use. I am in no way a tactical guru but I would go with the bungee sling…and probably one that I could adjust without having to tie a knot in it. I also assumed this was going to be used on a tactical shotgun…otherwise I would not go with a bungee setup.
"All the great things are simple, and many can be expressed in a single word: freedom, justice, honor, duty, mercy, hope." -Winston Churchill