Frank Borelli just published and article discussing his 10 year old G19. One of the few mods made was the addition of the Big Dot. Here's what he had to say, "The other modification I've made to my Glock 19 is the addition of XS Sights 24/7 Small Dot sights. This shallow-V rear and easy to find DOT front makes quick sight alignment in high risk time compressed situations easy to find and line up. As much as everyone talks about the importance of the front sight, I think these sights would be obvious in their value. My qualification scores haven't gone down at all since I installed them and in some instances my speed of shot placement has improved."
Now, I have yet to see Borelli write a negative comment on a piece of gear. He provides, however, a perspective of a third party. He experience mirrors mine. The Big Dots aren't for everybody or every mission. I'm not a SWAT dude or sniper. My primary concern is dealing with a large motivated thug in close quarters. Under these conditions, the Big Dot shines. If I was taking head shots across a parking lot, I'd find something else.
FWIW, I routinely see folks who turn up their nose at gear without giving it a fair shake. Running a couple of mags thru a gun and calling it no good is a bit short-sighted. The BD's do take some getting used to and you have dial in on your hold for longer/precision shots.
I note that Borelli is running a small dot. The principle still holds.
Edited cause I caint tipe.