I love them for a defensive/ fighting weapon. I use them on my every day carry G19 and would not think of anything else.
However that being said, they are not a good choice for a gaming gun. They don't score points well at the longer ranges. You can still use them and do well but for a gaming gun there are better choices. But they would definitely score bad guys down in a real self defense scenario.
I had them and enjoyed them, my only problem was picking them up well at night. I am not sure if it was the sights or me, but I went to something else.
Last time I tried them, several years ago, they didn't seem any faster than indexing off the slide, and slower than normal sights for precision shots. YMMV