Yeah that was the deal for me, the monos cut so much better with the huge frontal area when they pop open. The Sub-X was hit or miss, and even when it opened it's half the size of what monos open to. With a sub there's not much energy to work with, so you have to cut as much tissue as you can. I think the right comparison is broadhead vs field point on an arrow.
What size are you seeing to shoot? I don't see a lot of the huge ones around me, otherwise I'd be using a bigger case honestly.