I disagree with the "G27 kicks like a mule" comment. It's all what you get used to. I find my G27 to be VERY CONTROLLABLE and actually enjoy shooting it far more than my other pistols. I purchased the gun in March and have 600-700 rounds through it. Great gun. And since its my CCW, I want a caliber I TRUST to do the job. 9mm may be fine, but given a choice, I think the .40 has the edge.