I had been curious about the Wild Country Superlight Rocks for a while so I bought some to try out. I've placed them several times now, and they seem to work just as well as other nuts I've used- the shape is different than others and so you have to place them differently, but in some ways I think a nut is a nut.
But. Apparently they way they make these light is by making them less strong (not terribly surprising, I guess). They're rated to 4 or 6 kN, whereas normal "heavy" stoppers are more like 6 or 10 kN. So...
Discuss.