Guess it depends how you are using your gun.
For a carry gun, short can be easier to conceal. In a panic deadly force situation the accuracy is more the shooter then the gun. With minor motor skills and depth perception shuttng down on a physiological level, the gun will be more accurate then you can be.
If you are target shooting, hunting, or other types of shooting then the longer barrel will give you more velocity, and i think a flatter shot.