Handguns & cartridges for self-defense often come down to preference, sometimes subjective.
When the .40 S&W was introduced, I had no opinion of it. Around 1997 I bought a P-229 in .40 S&W. It is the most reliable handgun I own, and that includes revolvers. I have come to believe that the .40 S&W is the second best self-defense handgun cartridge. I'd rather have a .40 S&W than a .357 Mag. If fact, for many reasons, I do not consider the .357 Mag a good self-defense choice. Besides it being a revolver with limited capacity and time-consuming to reload only six more rounds, its muzzle blast is disorienting, its muzzle flash blinding, and its recoil, especially with light guns, excessive. All of these factors cause sight picture retention -a potentially life saving criterion extremely crucial were a bad guy shooting at a good guy- dicey at best.
For self-defense, I prefer heavy for caliber bullets. I am not if the light & fast corner. I want a bullet that will penetrate, preferably through-and-through. I'd much rather have through-and-through penetration than a bullet that's supposed to expand. I will go with an expanding bullet as long as I don't have to compromise what I consider more crucial criteria. I do not like frangible bullets. I want a self-defense bullet to retain its original weight.
Since .40 caliber self-defense projectiles are optimized at 180 grains at a nominal 1000 FPS, I see no benefit of the 10MM for that application. I'll take more .40 S&W rounds than less of the more powerful 10MM rounds. The 10MM would be superior for trail use.
I've remained of the opinion that the 1911A1 in .45 ACP is the best self-defense handgun. However, a P-229 with 13 180 grain rounds is a very close second.
I would definitely recommend the .40 S&W for self-defense. And I consider the P-229 one of the best handguns made.
For those who prefer the 9MM, .357 Sig, 10MM, etc, I'm good. After all, your choices will have to be what's right for you.