Megs Quik Clay (grey) is a HUGE improvement over the last one that I tried. It did not fall apart and was actually pulling some contaminents out of the paint. I would say it performed as well as my measuring stick which is the Mother's clay.
Now for Megs new agressive clay the C-2100 is GREAT CLAY!!! Here is how I judged it. After claying the car with Quik Clay (BTW, I used it with both soapy water and QD and it performed the same), the paint still felt a little rough. So I brought out the Mother's clay and re-did the hood, roof and back lid to see if the Mother's would smooth things out better. It didn't. In addition, using the Mother's clay I began working on a spot that had another color on it, like the car had been run into by an red/orange car or some other object. Neither the Quik Clay or the Mother's clay would get the foreign paint off. I thought this would be the perfect time to test the "New" aggresive clay the C-2100.
I began to rub the new clay on the foreign paint and it started coming off I than began re-claying the top half of the car. The strange thing about the roughness of the car was that I could not see the contaminents, only feel them. After claying with the C-2100 the paint was smooooth. I felt the clay and I could feel the bumps on the clay but again, I could not see them.
I don't know how clay compare to each other in terms of aggressiveness but I did find that there can be a big difference.