Little recoil, loud, lots of muzzle flash; if you're a good shot your assailant will never know what caliber you used to neutralize the threat. Then there's that rhetorical question that always comes to mind in this type of discussion: What caliber would any intelligent person really want to be shot with?
The rounds designed for short barrels (CritDef, PDX, Gold Dot) are pretty low flash…it’s definitely a lot more than, say, .22LR out of my S&W 43C, but it’s not a fireball like you’ll get out of rifle-designed WMR ammo (Maxi-Mag, etc).
And…there’s a critical flaw to your question—and that is, an intelligent person is likely NOT going to be in the situation where they’re going to get shot…it’s those folks who don’t GAF that are the problem.
That being said, though…the odds are stacked against you ever needing to use a firearm in defense. If you ever do, it’s a lot more likely that simply producing the firearm ends the problem with no shots fired. Should shots be fired—not even hits, mind you—will usually end the issue…but even then, 2-3 hits regardless of caliber, bullet type, etc—is a fight stopper in the vast majority of cases…
Yea, I know I just argued both sides of the issue, because both sides are equally valid, and have their strong points and weaknesses.
So, you pays your money and takes your chances.