it's like a springco, both springs compress at roughly the same time. From what I've been told, the beauty of the RM lies when the slide go's back into battery, reducing muzzle flip. I tried it, didn't like it and put my springco back in.
I had an STI Recoil Master and didn't like it. Recoil was more than with a SpringCo. I gave it 2 matches and shot terrible, I just didn't like the way it felt. The SpringCo is back in and I shoot just fine now