I carry a Kimber Pro Carry 1911 in .45 ACP because I was trained on the Colt .45 ACP 1911 when I was in service, and thus, the 1911 is second nature to me in it's operation; the fact that the 1911 design fits my hand well is also a large consideration for my choice of a carry weapon.
As for caliber, well, this issue has been hashed and re-hashed ad infinitum for decades, and I agree with Maverick...
The argument will live on irregardless of the facts since handguns / caibers are a point of subjective opinion for many who only have range experiance to base it on.
The key factor in any fight is shot placement. A center punch to the forhead with a 22 LR is far far better than a periferal hit with a 500 S&W. Shoot what you can hit with, not what some wag on a forum touts as the solution to all problems.
...and it is the reason I also carry a .22 Magnum S&W Airlite as a back-up!
You can argue ballistics until you are blue in the face about how well one caliber performs against another, but when all is said and done in a fight, it all comes down to where you placed your round while you were under extreme pressure, adrenaline was coursing through your veins, your heartbeat was highly elevated, and your hands were shaking! I once read a Police Coroner's ballistic study on wounds in which he stated that hollow point rounds didn't perform as well as regular ball ammunition because clothing tended to clog the hollow point and did not allow the hollow point to perform as advertised. Again! It is subjective and really is all about shot placement.
Personally, I love the 1911 design because it fits my hand well and I have been well trained on its operation. I also love my S&W Model 19 in .357 Magnum, but it doesn't hide as well as my Kimber.
One last caution about 1911's, and for that matter,
any auto-loading firearm; once you jack a round into the chamber, you
always have a round in the chamber! Always, always, always assume that there is a round in the chamber! A common mistake made by people who are unfamiliar with auto-loading firearms is to remove the magazine and
forget that they previously had jacked a round into the chamber and by simply removing the magazine, they thought the gun was safe! No auto-loading firearm is safe until you have removed the magazine and locked the slide, or bolt, to the rear and can visually verify that there is no round in the chamber!