Im not a fan of either really...both let the other guy know just where you are or are approaching from...bad thing if he's got a gun as well. Though if I had to choose, I'd go with light over laser. Glow in the dark sights are really good to have
The lights have an on switch. Lights are great because you get to see what your shooting at, or shouldn't shoot act.

yeah, but i feel you, if you want to get all ninja, light needs to be off. I'm guessing here, but i bet that if that robbery saw the rail light, he would just have ran away.