The real advantage of a 1911 is the simple, reliable design. The .45acp simply outperforms smaller rounds as well and before a silly communist in the White House agreed with the UN to start destroying armories full of durable and proven military small arms in .45acp and 30/'06, we had millions of militia weapons available to a citizen militia in the event of the kind of emergency we now face, all of which were easily rebuilt and used two standard and proven military cartridges.
My points are these: The .45 is a proven fight-stopper, low-pressure, low-velocity, thereby easy to control round, once one gets used to the low, throaty Booooom, and the push, rather than snap of a 9mm+P, which, just as ANY .38, it needs. It's a well known axiom that a .38 needs barrel length in which to burn powder, to build up pressure/velocity, and be effective at all. The .38S&W, which the .45 was designed to replace, was a famous non-entity. It wasn't until the early-mid 1960's, I think, that Lee Jurras pioneered the high-velocity .38 round, with his "Super-Vel" load, also using inverted, hollow-base wadcutters to maximize the anemic and deficient practical performanc of hot-loaded .38s, especially in short barrels. Many police departments were still using the notoriously ineffective 200gr. round-nose .38 at that time. Not until Gun-magazine testing in the 80's and 90's did people accept the fact that, if one disregards the fire, side-spray and awful racket, that a short-barrelled .38 or even .357 was delivering anything worthwhile downrange. Now the "automatic" craze, which is fine, but does not negate the proven physics and practical reality. Here we have a LESS than .38 caliber bullet (.355), of a nationally police-proven miserable bullet shape, made even worse by not being softer lead, but guilding-metal jacketed (has its good points, however), in a pistol which does not like to cycle lead, and often hollow points, and rarely of different weights and designs, of smaller parts and surfaces than the slow, large, boring yet battle-proven .45ACP and its intimidating (NYPD Stakeout/Undercover "Anti-Crime" Detectives' personal choice, when possible) muzzle "hole," being all-around smaller is therefore more magazine-sensitive, add to that a polymer frame which is famous for softer than the usual sharp snap 9mm recoil, but due to the frame actually flexing, which is clearly observable using photography...making it more susceptable to jamming due to "limp-wristing," which less experienced/trained/strong shooters are prone to do, incidentally the ones the package is frequently marketed to (although the internal mechanism is remarkable, with the exception of "no second-strike capability", which keeps some P.D. Armorers of my acquaintence averse to carrying it--Browning designs and all single actions don't have it either!), well, that's a long way to go to accomplish little more than having a "perhaps" slimmer, less complicated to function, high capacity because the first one or two didn't do enough (like you have time to wait!), that NEEDS to be fired more, which adds to the chance of a jam at the least convenient time. Wow. Impressive. Makes a six-shooter look like the genius' first choice. Suddenly, in the supposed age of the Fritz-helmeted, GPS-wired, night-vision "Infantryman of the Future," Barney Fife with more of the right ammunition could stop a fight with less, simpler and more reliable actual shooting being done. Is this progress?
The .45ACP, whether one likes it for whatever reasons or not, works. It is the same size going in, even the dead-reliable functioning Ball, than the 9mm will not be coming out, which it may or may not. 9mm/.380s' hollow points fill up with material, creating a de-facto FMJ, negating the complicated and unpredictable (speak to experienced pathologists) "controlled expansion." The round will reach across the street flatter and faster, and being more pencil-like, probably penetrate better. That is true. This is why these conversations continue to take place, and why people like me carry both, at different times perhaps, and for different reasons.
The .357Sig in as common as a hen's tooth, probably works well after impact...basically an automatic .357...but awfully small, anged sharply, high pressure, demanding of the already clockwork-like action (why I like to carry lower-velocity, softer bullet loads in my beautiful High Powers), and is largely unproven in the field or street. Potential, though.
As for swords or guns...properly-mounted and utilized bayonets. Oh yes. The Old West practical technique of "buffaloing," or slugging your adversary over the noggin with ones', in those days, probably 7 1/2" barrel...still works. However, several well-seasoned active and retired NYPD Detective friends have reported to me that when applying the technique, always hit with the muzzle, NEVER sideways, or on the trigger-guard. The cylinder may unlock, and with a Chief, the guard WILL crush around the trigger...better use a Model 10 or something heavier, like a Det.Special...or you may find yourself with a once expensive steel rock in your hand...and hoping your teeth are sharp enough for what may be coming next! Another Anti-Crime gent advises to carry a Ruger revolver, because at muzzle-to-nostril range, he often gets asked..."is that a Magnum?" because of its non-S&W shape. Intimidation must work pretty well for him, as we were always allowing him to use our gun-shop bathroom, to wash the meat and hair out of the action. He got free WD-40 from the boss.
Well, as we say in New York, usually with more of a crooked grin than since 9-11...Have a nice day. Happy trails, all.