Surprised no one's mentioned two things - - -
1. The three-inch guns have a full length ejector rod, and thus will completely extract/eject .357 empties. This, even if you don't hit it a solid lick with heel of the hand. It
COULD make a difference some evil evening.
2. Unless you're into pants pocket carry, the three-inch bbl revolver is actually
easier to conceal. The added half-inch probably won't show beneath the tail of your jacket or overshirt. If it does, concealment was marginal to begin with. BUT, the added barrel presses against the hip and keeps the butt pushed back into your side. Any size revolver with insufficient barrel, even in a decent holster on a proper belt, tents to sag outward, and you get burned by the butt bulge rather than muzzle peek. AND, with an IWB holster, or when you just cram gun
sans holster into your waistband, the added length may keep it in place, where a short snubby had been known to pop out at inopportune moments.
Given the right holster/belt combo, many people hide four-inch magnums and full-size 1911s, while others of similar build print badly with a two- or 2-1/2 inch K-frame.
Best,
Johnny