Not being into short-barreled handguns (less than four inches), I have no preference regarding the three-inch ones but five inches is a perfect, in my opinion, length for today's underlug barrels. The balance is better than the next shorter and longer options without sacrificing much in the way of sighting radius or muzzle velocity.

In a K-frame like a Model 19 or 66, four inches feels the same but you are losing some velocity over a six-inch. I shot in a lot of PPC and bullseye matches 40 years ago with a four-inch Model 19 and did quite well, so they can be accurate but if downrange energy is your goal, four inches can detract from that.

Ed