A correction on my last post. I just looked at different ballistic chart that lists a .357 125 grain JHP at 1450 fps. You get the picture though. Full power .357 loads are pretty hot for a short barrel. Hopefully the new short barrel load at 1000 fps will be a good compromise between .38 +P and full power .357 loads.
The best stopping power is a complex mix of many different factors, including how fast the round is traveling and what it does when it enters the attacker's body. While the classic .45 ACP round is large, it's also relatively slow, with an average velocity of 850-900 FPS for most types of ammo.