As you are reading the .40 ones, the caliber debate is worth a mention as well. There has been a resurgence of 9mm over the years due to reduced recoil, lower prices and increased capacity. Nevertheless, even.40 S&W has a stronger impact than 9mm and a significant number of shooters like that middle ground between 9mm and .45 ACP. The disadvantage is that it has a snappier recoil and tends to wear the gun out more with time. Personally I believe caliber is not so important as compared to where the shot is and the way one will shoot the gun. When you are comfortable with.40, SIG Sauer P229, Heckler and Koch USP and Smith and Wesson M and P40 are all proven platforms. The most appropriate is the one that fits well in your hand and you can shoot it accurately and consistently.