^^ +1
I mean, how does one really test these sorts of things? Measure and assess the truck, install company XX's kit, head out and beat your truck to death, uninstall, remeasure and reassess. Then rinse and repeat for each new kit? I dunno if anyone is going to be willing to go there.
Short of that, maybe talk to each vendor and get a guarantee that you can return the kit if unused and in new condition. Then get them all in your hands, lay them out across your driveway and 'compare' that way. Keep your favorite, and send the rest back? I can see that sort of thing being fairly informative.
Beyond that, I think pics and thoughts and comments already posted here are probably going to be your best resource.