Not saying that I wouldn't be up for it as an experience. But can't really see the upside of MMF in a shop. I know with a FFM I'm paying double, but in return I have two bodies to play with. I would assume in MMF, you're paying double as well but for what? Unless this a way for dudes to get their Bisexual on.
I do find the idea of playing with a couple very hot so I guess I can see the appeal.