I've had a lot of experience with .40 S&W. For the last several years of my dad's law enforcement career, both agencies he worked for issued it, so we got a lot of free ammo and ended up owning a couple guns chambered for it. I grew to dislike it a lot, preferring 9mm, .45 ACP, and 10mm Auto over .40 S&W. It always felt like a cartridge designed by committee to me. "Well, we want to have high capacity like 9mm, a large diameter projectile and heavier weight like .45 ACP, and higher velocity like 10mm." and it just doesn't do either of them very well IMHO. And with modern 9mm being loaded being loaded with more advanced and effective bullet designs, and with how snappy the recoil is on .40 S&W, I feel these days 9mm totally out classes .40. You have higher capacity and lower recoil allowing one to put more hate on target, more rapidly, and more accurately. And if you're wanting a "big man-stopper" cartridge to carry, there's .45 ACP +P or even .45 Super, 10mm Auto loaded to the hotter, original specs, or .357 Magnum if you're not worried about capacity. Back in the 90s and early 2000s, .40 S&W was the darling of law enforcement, but these days even cops are moving back to 9mm.
