Kahn Nance

I am curious to know what the different opinions are regarding agitation/bite work training with an agitation harness vs soft collar. I've asked around and Ive heard many people say they prefer the agitation harness because it offers less restriction on the dog overall and it is particularly good for younger dogs. Others say you only go to it only if the dog has a physical problem with using a soft collar first but the soft collar is the way to go.. Does it really make a difference either way..? If so, why..? Thoughts..?