I have shot lots of 9mm, 45ACP, 40, 357 Magnum, and 357 SIG. I would agree that the 357 SIG is the best handgun personal defence round. The 125g version of the 357 SIG basically duplicates the ballistic performance of a 357 Magnum with WAY less recoil. The recoil on the 357 Mag is very short but high, whereas the recoil on the 357 SIG is slower and has a notably lower peak.
When I worked briefly with the Texas Department of Public Safety (The Texas State Police), the big story that everyone told was about the time when the department changed from 45 acp to 357 SIG. A rookie and a veteran were teamed up, and the vet had the 45 and the rookie had the new 357 SIG. They were in a firefight with a felon who was inside an over the road tractor. The veteran's 45 acp rounds were denting the truck door but not penetrating. The rookie's 357 SIG rounds went clean through the door AND dispatched the felon. It made a big impression on the troopers. The word got around that the 357 SIG was "like being hit with a bolt of lightning" and would bring down a perp even if he was on drugs.
Sadly, the department later changed to 9mm some years ago. But a LOT of state and Federal agencies use the 357 SIG.
When I moved to Canada, I found that 357 SIG is very hard to get reliably and at a decent price, because Canadian Law Enforcement agencies apparently do not use it anywhere to the extent that the U.,S. ones do. So as a practical measure I changed to 9mm, but always shoot 115g 9mm rounds that are 1300 fps or faster. That's not as good as the 125g SIG 357, but it's better than the 45 acp and the 357 Mag. I like the terminal ballistics of the .40, but I also value accuracy very highly, and the SIG P210A is the most accurate handgun I have ever owned, and that only comes in 9mm, and is way more accurate than any .40 I have owned except for a custom compact pistol built by Fred Craig, which is illegal to own in Canada because its barrel is under 4-1/8" length, so I had to sell it to another Craig collector before I left the U.S.
Jim G