I've used backquivers for 20 years and have tried all the other types, but stay with the backwarmer. For me it's the best kind. Most of the quivers I see are too stiff, too small, too short, not hanging correctly and not used correctly. Like David says, a properly made Hill style backquiver is a joy to use, doesn't spook game, is quiet and can carry your lunch.
I've had deer watch me draw an arrow out of the quiver and not spook....so much for that theory. If the quiver hangs more off the shoulder and horizontal, the arrows will not rattle....so much for that theory. If you learn to slide the quiver around with your bowhand when going through brush, they won't be hanging up and making noise....so much for that theory.
The greatest majority of bowhunters I've heard talk about the negative aspects of a backquiver, have never, ever, used a good one correctly.