I've never had to use my pistol for self-defense, yet, so what I have to report is strictly from practice sessions -
I found that with good light the iron sights aren't that hard to use. I get pretty good results without taking careful aim, including deliberate "double taps".
However, in dim lighting, the lasergrips really make a difference. Line up the dot on the target and squeeze. That's where it hits, including double taps.
I'm still practicing with a flashlight, and it doesn't "wash out" the laser, but it does let you see the target in complete darkness. I don't have it mounted on the pistol -- I hold it with my weak hand.
IMO, practice with what you have and use each sighting system when it is at its best.