I'd like to add something intelligent to this thread....Then I changed my mind...
.357sig > 9mm
Seriously. I personally prefer the .357sig that is why I traded in my G17 for a G32. But that doesnt mean everyone should prefer it. The best way I can describe the difference is its a more "potent" round. More devastating while pinking, and flatter trajectory while shooting at distance.
I hope I dont and doubt I'll will ever need to shoot a human being. But if I do I want a weapon that I can handle properly and that functions reliably, I'll worry about caliber size and ballistic numbers later...