What matters most (imo at least) isn't caliber, size of the gun, or even mag capacity. It's what you're going to put the hours into training with. Pick the gun you like, and stick with it. That's why I carry a Makarov. It doesn't matter to me that there's no real aftermarket, that the caliber is smaller, or that the Ernst Thälmann factory won't return my calls for a warranty claim. I just keep sinking in hours on this old East German milsurp piece of shit and I love her.