I'm no expert, but personally, if I had to be confronting enemy soldiers, I would rather have my glock .45 or 1911 .45 than the beretta any day. Not wanting to flame the caliber wars any more than they already are, but I'm with you on this one. I've fired both guns and both calibers, and if the s**t hit the fan, give me a .45 anytime.
I'll take knockdown power any day of the week. And I've fired the .45 often enough (25+ years now) to put it where it will do sufficient damage to put down the bad guy.
I personally don't go for the caliber flame wars. SOME people are two small to handle the recoil of the .45. Some people just don't like the way the caliber handles. Me I get along w/ both just fine. I feel shoot the biggest you can control.