Don't get me wrong, Mags - I can punish the center of a target that I've run down a well-lighted shooting lane, but I don't expect that to be the situation I have to defend myself in. For self-defense, there's no such thing as too much going for you.
Still, I don't use the laser for shooting at the lane (though I've tested that too). The sights on the slide are always more accurate and won't need re-adjusting. Given the time (and space) to use them, they're superior!
Also, about activation and batteries...
At least for my Sig, the Crimson Trace grips have a front-activation button that's under your middle finger's middle knuckle (front of grip, below trigger guard). Working it doesn't bother me. If I got really tense and klutzy, it would be on because of a tight grip. I know that C.T. doesn't have that feature on grips for all models of gun, though. With some lasers it really is a switch-on beforehand.
C.T. also has a cute deal for the batteries. When I got mine, they had an offer to send you free batteries every year. I don't figure I'll be activating the laser too much, but I could go and buy a battery if I do use it that much. An average night of self-defense is going to require using the laser for a max of what, five minutes? That's not too much drain, really.