Size (and distance) matters
As a newer pistol convert from the good ole clays sports I can say that all these guns are great for what they're intended to do. Personally, I love .22LR it's a heck of a lot of fun to shoot. DA revolvers, SA revolvers, autos...its all fun. Yes, but it's useless for Self Defense!(some say). Yes it probably is but if you're not 50 and a former Marine a .45 isn't going to handle well in your hands. Most of the guys on here have fired thousands if not tens of thousands of rounds of pistol ammo. So IMHO if you don't own a .22LR to train and have fun with your nuts. Particularly if you are introducing new shooters. My brother gave his wife a 9mm and just thought she'd be a good shot. Guess what she got scared of the recoil and never hit anything and gave it up. Now other guns have places too. For a real life someones coming and it looks like they are going to hurt me/ my family at close range most modern guns work. A 380acp is a good light self defense gun but you have to train with it at the right distance. Personally for center-fire I shoot 9mm and .38spl. They are cheap(er) to shoot and for most applications you can get good ammo that will do the job if you need it to. 45acp is great and no doubt it will put down your target but if your not extremely well practiced it is not the weapon for the average Joe defending his home and family. Point is all these guns and all the ammo types are good if applied with respect to their limitations. Pick which one works for you.