I have a ColtMustang stainless loaded with hydrashoks (or whatever they are called now). I also have a smith 642 airweight, loaded with Winchester SWCJHP +P ammo.
I tested the ammo on 1 gallon plastic jugs, filled with water. The 38 clearly did more damage to them. The exit holes were larger, and the jug itself was deformed more. However, after seeing what was left of the jugs, I can't see someone getting back up after an upper body hit, with either gun. Now if you live where the populace has 6 layers of clothing becasue of the weather, go with 38 caliber 158 grain wadcutters.
The 38 with +P has a bit more recoil, but still second shot controllable. The mustand, being flatter, and myself being a smaller guy is more easily concealable, in both IWB or pocket carry.
Forget about "range" accuracy with either gun. They are meant for bad breath distances,or as we used to say when hunting, use it when you are about to be eaten......
I don't feel like either is a mouse gun and will continue to carry either. Remember:
"two in the chest, one in the head;
even the jolly green giant will fall down dead."
Whatever you decide-- practice, practice, practice...