James, the only one I have any experience with is the Glock in the new GAP and I was not impressed at all. Supposedly, their main reasons for this new caliber is less recoil and close to the same performance as the .45 auto. I'm used to shooting heavier 1911 style autos in .45, so really the lighter Glock in GAP didn't seem to have that much less recoil. If the reason you're looking at the GAP is less recoil, go with the model 21 and ease up on the powder charge on the reloads. just my .02