ALL handguns, and everything about them, are compromises on a number of things. Weight, concealability, capacity, caliber, power, function, shape, trigger, sights, grip, etc. And let's not forget price, especially these days! And let's not forget esthetics, too. I'm a firm believer that esthetics may indeed be something very important for some people. I know it is for me. I, for one, won't own a Glock simply because they're ugly as sin in my eyes and I don't want to own an ugly gun. This, despite the fact that Glocks are by any measure an outstanding pistol. Fortunately, there are a great many other pistols to choose from which do appeal to my eyes. Since all handguns are compromises on many different features, what may suitably fit for one person may not work at all for another. And yes, caliber is part of this. .380, for example, has been described by many as having mild recoil. Well...sure, depending on what gun you fire it from. My wife's PPK/S will happily let the webbing of your hand between your thumb and forefinger know that it's very capable of hammering the bejeebers out of it, much more so than my 92FS. Yet it's a much easier to conceal pistol than my 92FS. Some handguns I own were never bought with self defense in mind at all. While I'm quite sure .45 Colt will be effective against an attacker, I'm not about to shift to my Colt SAA as my concealed carry preference. Also, even within a given caliber, there can be a wide range of performance characteristics based on mass of the bullet, design of the bullet, velocity of the bullet, if the ammo is designed to work better out of a short barrel, etc. Modern ammo choices these days are far and above what they used to be decades past. There are plenty of suitable self defense rounds in a great variety of calibers these days. Pick something that will function flawlessly in your chosen handgun and go with it, I say. Frank Ettin has posted this elsewhere on the subject of calibers/bullets. Choose your balance: So as a rule of thumb -- More holes are better than fewer holes. Larger holes are better than smaller holes. Holes in the right places are better than holes in the wrong places. Holes that are deep enough are better than holes that aren't. There are no magic bullets. There are no guarantees.