
Uhhgg. Caliber wars when it comes to defensive handguns are so played out. Here's a clue..
IT DOESN'T REALLY MATTER!
All handguns are weak-sauce compared to long guns, the only reason we carry handguns is because it's to cumbersome to carry a long gun everywhere. Whether you carry .380, .38 special, .357 magnum, .357 Sig, .40 S&W, 9mm, 10mm, .45 ACP, .44 magnum blah, blah, blah.
The round you carry doesn't matter so much, as that you know how to use the handgun. The greatest most all-powerful-magic-super-duper cartridge and handgun combination will do you no good if you either aren't comfortable wearing it, operating it, or can't hit jack squat with it.
Find a handgun that's reliable, that you can operate with your eyes closed and in any position, that you're comfortable wearing, and that will shoot where you point it. When you find it, that's the gun for you... don't worry about what caliber it is. Then, practice, practice, practice.