I like them, just train yourself to take the shot without hesitation if you don't see the red laser dot appear like you expect it to. Your finger can miss the button, OR the thing could malfunction, or the batteries could be dead, etc.
If it doesn't work instantly, use the sights or your best pointing technique to get off the shot anyway.
I have one set of C.T. lasergrips, and others in my family have a couple more sets.
P.S. I've noticed that they don't hold a zero with great precision, but who cares on a short-barreled self defense carry pistol anyway? If my groups are 3" off at 30 feet, I'll still hit the bad guy center-of-mass.