I have carried 3", 3.5", 4.25" (Commander and CCO), and 5" 1911s, and I prefer to carry the five-inch guns on the belt and the 3" guns in shoulder holsters. For IWB carry, the longer slide is nice as it helps anchor the gun and the extra length does not cause any printing issues. The sight radius makes shooting the five-inch guns easier than the shorter variants.
The shorter guns work for me when I must carry in a shoulder holster such as during long periods of time in vehicles. I prefer, even for this application, steel frames for both less perceived recoil and durability as frequent practice with the smaller guns is needed to keep accuracy sharp. I actually shoot more rounds through the smaller guns as I have found that shooting a five-inch gun well is very easy after shooting the 3" guns.
For my needs, the Commander and CCO are neither fish nor fowl. The shorter slide is not a plus for IWB but is still too long for a horizontal shoulder holster, the Commander frame is the same length in IWB as the five-inch gun, and the round butt/Bobtail treatments on the five-inch guns are as easy to conceal IWB as the Officer's ACP grip frame. The 3"/3.5" guns (like the discontinued Defender Plus and Double Eagle Officer's ACP) with full-length grip frames are great for horizontal shoulder carry and eliminate the need for Officer's ACP magazines.
So, for now (as I am always evaluating as both offferings change and I age), I am sticking with five-inch guns on the belt and three-inch guns on the shoulder.