Oh, I know that some of you are gonna go all ".45 or nothing" on me but just watch and learn. The "Caliber Argument" has been raging for decades, even though it was already settled a long time ago. As an aficionado of .45 cal. I can tell you, first hand, that big calibers "just feel better." However, feelings shouldn't enter into this equation. The bigger questions are "what is best for your needs" and "how little can I get away with?" There's a question that has to be asked. "How little can I get away with" means that if you're a small statured shooter you may not be able to handle a big caliber in a big gun. Look, I'm a big dude and I can muscle .40 cal around with little issue. I can even handle a 10mm G20 Glockzilla with little trouble. However, I carry a Glock 19 in 9mm. Why? Because it meets my needs of a small, concealable handgun that carries enough ammo to keep me in the fight - and it plays nice with ALL the accessories out there. I used to carry a Glock 21 in .45 cal. I loved that gun it suited my big hands quite well. Unfortunately there was little in the way of holsters, accessories, or support for it. I sold it and focused on Glocks 17 and 19 and have never looked back. Reality dictates what you carry, think before you commit.