I have been shooting NMBHs for 6 or 7 years. I have heard the claims about the recoil handling ability of the Bisley grips. I, too got one of the SS Bisleys and I wasn't that thrilled with the grip. I got thicker grips, and that didn't help. Then, counter intuitively, I got thinner grips, smooth Gunfighter grips. That fixed it.
On the NMBH, I like smooth gunfighter grips for high recoil applications, and checkered gunfighter grips for low recoil like CAS. I sometimes take standard Ruger grips and thin and contour them to my likes.
Now, I find, with smooth grips, the recoil handling ability of both the Bisley and NMBH is about the same.