I like the 24/7 Big Dots on my Kahr Mk9, they are definately well made sights, and they are excellent for self-defense use out to 20 yards or so. They are lacking for precision, but for high speed you really can't beat them.
After saying all that..........
I use Trijicons on my P99, Meprolights on my wifes P99QA, and save the Big Dots for my up close and personal Kahr Mk9.
I get much better accuracy from the traditional sights on the full size pistols, and don't really give up that much speed. But on the sub-compact Kahr, the Big Dots are the best sights made IMO.