I "suppose" that given similar pistols a 45acp maybe has more recoil for me than a 9mm, but in full-sized service pistols it's apparently not enough to matter. For me 45acp has never felt like a high-recoil round (though admittedly I have never owned a small handgun in that caliber). Of the three, 40 caliber feels just a little bit snappier to me, but it's still plenty comfortable. I have full-sized Tanfoglios and Ruger P-series in all three calibers. They are all nice big pistols with plenty of grip for me to hang onto. To me the difference in recoil in those three calibers in nearly identical pistols is barely noticeable and therefore unimportant. It seems like putting bigger holes through things should logically cause more structural damage, but the 9mm pistols generally hold a few more rounds... so, again, I'm personally fine with any of the "big three".