I work for a large PD, about 5000 officers. When I started, in the early 1980's, we had to use .357 sixguns for our rookie year, then could switch to autoloaders. By far, the popular choice was .45 ACP, and bad guys hit with .45 ACP fell when we hit them in the right places.
In 1997, we (the PD) changed to all-.40 DA autopistols for new primary duty weapons, though nobody had to switch from what they were already using; existing weapons were "grandfathered." (We buy our own weapons.) By now, through attrition and changes of assignment of older officers, most duty pistols on the street are .40, and when we hit bad guys in the right places, they fall. Same as .45 ACP. We patrol a big city, and do shoot plenty of bad guys over time.
I went with the .40 voluntarily in 2004, setting aside .45 pistols, and have not lost any sleep over it. My present P229 duty pistols are a great fit for my hands; I would not go back to a 1911 as a primary weapon for street patrol duty if offered the chance.* I choose to use the same P229s for most concealed carry on my own time. I may revert to a 1911 for concealed carry after retirement, or use other than .40 for plainclothes/non-patrol use before retirement, but that would be because of the weapon itself, not the .45 or other bore size.
*To be clear, I think the 1911 is a great pistol. Our mandated retention-style duty rig, plus my ultra-skinny hands, long arms, and short torso, created a perfect storm situation, when drawing a 1911, that caused me have issues attaining a consistent and proper grip on a 1911. This in an individual issue, and nothing I said in the above paragraph is meant to disparage the 1911, or those who carry them.