Pure BS. Bullet performance relies on a combination of weight, velocity and design. The .357 amassed an incredible reputation amongst street cops who's agencies carried it back in the late '70s when 125 gr. loads such as Federal and Remington offer hit the streets. The best .357 loads are absolutely ferocious at close range and lack nothing in energy delivery, or performance. In a podcast on proarms.podbean.com , veteran street cop and multiple gunfight winner Keith Jones goes into detail about the success his agency enjoyed when they switched from the .38 to the .357 after they geared their training to help their officers master the sharp crack and recoil of the .357. It was of interest that on average, more perps stopped when hit marginally with a .357, had to be shot less times, and ultimately more of them lived. IIRC, no officer had to shoot a perp more than twice to end hostilities. As others have said shot placement is the biggest factor and YMMV. I would also guess that the average police shootout is at ranges common to civilian CCW.

When top flight service calibers are mentioned, .38+P ain't one of them. It's more commonly compared with the greatest manstopping round, by far, of all time, the .380. Do I believe the .38+P is better than a .380? Sure, but at the same time, the comparison isn't made for no reason.

Has .38+P improved with bullet technology? Sure. Is it the best for most people? Probably and because most people will not put in the range time to master the .357, or perhaps for physical reasons cannot. Each of us has to decide which camp we fall in. In the end though, the .38+P ain't a .357.

Now .357 vs. .45? I don't think that there is a huge reason to expect one to out perform the other from standard service length barrels, given the better loads in each caliber are being used. However, a 3 1/2" .45 ain't standard length, the .45 is notorious for difficulty expanding from short tubes, and that's aside from the reliability issues that class of guns tends to display. Lighter, 185, or 200 grainish bullets may solve any expansion issues by boosting velocity. Myself, I would use a 5" gun, or switch calibers.

For a .357 gun (and I would get a .357 even if the plan is to run .38s) I would get an L frame for worry free use of 125 gr. .357 ammo. If you intend to use .38s, then a K frame would have the benefit of lighter weight and a lower bore axis.

As far as comfort goes, I don't base what I carry on comfort, I base it on "what is the biggest most powerful thing that I can conceal". I advise others to do the same. The weapons you have with you at the time are what you will be forced to fight with. If one chooses not to follow my advice, that's fine. It's a personal decision.

Good luck deciding.