Ok fair enough. My racks are on solid and dont move at all. Only have an awning mounted on them. And put a few things on them when going away. So I'll never test their max load rating. Do you know anyone that has had them fail?
I would call sliding all around the door jam and trashing the paint, which also caused the strap that my ladders were tied on with to loosen and fall off a fail.
Could of lost my ladders into on coming traffic or worse through them in through some poor buggers windshield.
Having an awning mounted to them will also be keeping them spaced and helping them not slide around i guess.
But you load them up and tie a good load of super tight and you will see even a good ratchet will pull them together, you just dont get that with the track mount.
My point is if you have the coin and are in the market for a brand new set up why not put on the system that works best and has more flexibility in the way of personalising the location and what you carry, for a few extra $ you can put on a set up that you cant go wrong with and will do any thing you want.