I think they put together a great system. There really isn't any strain on the ram box tie down system. The whole bakflip system is pretty light. I think the whole thing is like 70 lbs. I installed the kit by myself and lifted the whole thing into the truck and into place without any help. The only place it really anchors to the truck is the front two L brackets. The other brackets are really just places for the locking mechanisms to catch. The whole thing rests on top of the L brackets and the tie down bars, which are really heavy duty.
It was bone dry after a good rain storm the other day. It does use the inner rail as a collection system and has cups and drain hoses at all four corners. Mine have yet to be installed though because it's to cold for the double stick tape and silicone to set up.