In a stress situation would you need the lazer? If so do more training!
I like the lazer as I practice hip shots with the lazer then when I am comfortable with my shooting I turn the lazer off and hip shoot, with a little practice you can hold a 6" group at 20'.
If I was to have time to prepare for the situation I would turn the lazer on but do not rely on it. Just the fact it was on could be a deterant but not always.