There will always be a caliber bigger and faster than yours. I am a 45 guy, I like it better than 40 or 9mm, but its not as fast or heavy as the 50AE. Go with what you like. I happen to trust 45 over anything else given the choice, but in the P2000sk I carry 40 because 45 wasnt an available option. Given the option I'll be packing a 45. The recoil in the P2000sk in .40 is very manageable btw. People seem to have trouble drawing a distinction between the 9mm and a 22 or a bb gun. Keep in mind when comparing 9mm, 40, 45, etc the differences are often very small fractions of inches and ounces. I am comfortable with the 45, and I will go to it every time...but that wont help someone who cant hit the broad side of a barn with a 45...I would shoot the heaviest fastest round that you are comfortable with.