OP, I'm like 99.999999999% certain the JMS was joking. I doubt you will get any actual uses. Your best bet is to ask Massad Ayoob, or check for police shootings. From what I've heard, it is a very good human defense caliber. I have heard words like "bolt of lightning" and "one-shot-stop" associated with it. Both of those remarks came from the Texas State Police if I remember correctly. It has a good street record, and great ballistics. It should be especially impressive from the G31's longer barrel. I'm thinking a G33 will be one of my next purchases. I wanted a G26, but I feel the G33 will give me REAL 9mm ballistics (close to or better than a 9x19 shot from a G17), but out of a subcompact. Recoil is no big deal, but the blast is a little boomier. I think it's the best SD caliber in the small frames.
I guess my whole point of this post was to tell you not to get your hopes up about first hand shooting accounts with the caliber. Not many members here have actually shot someone. Those that have don't usually like to share them for some reason (not all), and there are not likely to be many that used .357Sig. But good luck!