Simply stated the .357 Sig is a waste. It is nothing more than a bottle neck .38 Super, before the Super was neutered in the 1960's or 1970's. The case capacity of water of both is about 10% more than the 9x19mm. As previously mentioned in this thread it is basically a .40 S&W necked down to 9 mm. You can get essentially the same real world (as opposed to advertised) performance out of the 9x19 by going to +P+ ammo.
No commonly carried defensive handgun for "two legged vermin" develops even 50% of the ballistic energy necessary to have any real "shock effect", or "knock down" or "stopping" power. Unless the brain, the spinal cord, a major bone, or a major nerve plexus is hit; a handgun gunshot wound is simply a deep or not so deep stab wound. Incapacitation, for a person who wants to fight, comes from loss of blood'; which can take time, like over 4.5 minutes on Black Tuesday in Miami in 1986.
Platt was fatally wounded early in the fight. He then proceeded to kill his shooter and shooter's partner, and wound 5 more FBI agents before being incapacitated by a bullet that bruised his spine.
Over 150 years of real world history has demonstrated that large diameter, heavy bullets, moving at reasonable velocities that enables them to make deep wounds have an advantage over small diameter, light bullets with big ballistic energy numbers.