I've loaded out many many GN/5th wheel hitch flatbed/enclosed/stock trailers.
I found it amusing when the guy said we should put a 2nd rail in the trailer. The 2nd rail was over and probably behind the trailers axles which makes a lighter pin weight but does add to the hitches draw weight.
Looks like a good deal for hauling heavy or light trailers. As with all things mechanical only time and duty cycles will tell if the aluminum stands up to long term service.