I use two roller cams on loop straps that go over/through the gear pile on the beaver tail.
I really like them, you can put more tension on the strap.
My only complaint is under high tension, unless the pull is square to the buckle, the strap may want to shift and/or fold and bind in the buckle. I'm sure a regular cam would have this problem if you could get the tension on it. As I see it, it's just the nature of the beast.