It's my opinion that the .40S&W is the ultimate compromise cartridge. It's small enough in diameter to load plenty of rounds into double-stack magazines, but it breaks that psychologically meaningful barrier of a caliber that starts with a "4" instead of a "3" or anything equivalent. That said, now I have to select between my carry guns from amongst my:
- Glock Model 19 with its 15+1 9mm capacity, or
- Beretta 96F Centurion with its 10+1 .40S&W capacity, or
- Springfield Armory 1911 with its 8+1 .45ACP capacity.
The difference between the 9mm (16 rounds total) and the .40S&W (11 rounds total) is the most extreme. The difference between the .4S&W (11) and the .45ACP (9) doesn't really seem worth arguing about, does it? Then my thought is this...
Is it really worth arguing in the first place? Probably not. If you're a fan of and comfortable with the .45ACP weapons, carry one. If you prefer and are comfortable with the 9mm, carry that. If you like the .40 because it makes you feel like you've solved a difficult conundrum, then carry it.
Me? I still make a choice every day based on how I'm dressing and where I'm going. Variety is good. Don't pick just one. Have one of each available and make your choice as each set of circumstances looms.