I prefer shot placement over caliber size as a rule. Now every rule has exceptions, for me I love .45's, 9mm, .357 rounds. That is just me and my .02. Shoot what you are the most accurate with, shoot quality ammo, shoot and practice often, then you should be fine. I feel strongly against carrying only one caliber for every situation. I carried a .22lr for years as a bug or mouse gun, I also carried a .357 or a .45 or a .40, unless I could only carry the .22.
Hit the threat in center mass with HP's and over penetration should not be a problem, miss the threat and not knowing what is behind it is a different story. The caliber debate will never end, the right caliber to carry can be found with some rental practice and common sense thinking.
Or you can just get a spray and pray Uzi and kill everything or nothing at all.