We've got a hinged lead in to easily install these on the sheathing. The design allows the clip, once on, to grip the sheathing so the clips can be pre loaded and the next sheet slid in place. No bending or clips falling off. Our customers have commented that the install has allowed them to take 1-2 hours off of the roofing job of an average size house.
We had them tested for strength and deflection and the result was they are stronger than the steel, in some cases more than twice the load bearing strength. The coastal areas have really been using them because they are resistant to corrosion from salt littered humidity. The web site has alot more info. The distributors like the fact that each size clip can cover a range of sizes, so they are stocking less different items.