The one you are most comfortable with. If there would be "the one perfect" sensitivity, then games wouldn't have the choice to change it. My personal rule is: Weapons with high aim assist and/slow fire rate/precision weapons (hand cannons+snipers) = low sensitivity. This is so I can feel the drag over ones head better. On a very low setting you can almost feel your controller stopping over the hitbox Weapons with low aim assist/high fire rate = (auto rifles/shotguns) higher sensitivity This is because you "spray" more than actually aiming and you need more movement flexibility to turn your character towards the target. You could also question, do you move the reticle more, then go for low, do you move more with your character then go high.