Two areas of concern:
1. Reliability. This includes battery life. To me, unreliable electronics and the need for batteries are concerns.
2. Eyesight problems. I have astigmatism. I was able to use a lower brightness setting and make the sight usable on my rifle. No idea if astigmatism would be more of a problem with a pistol.
I also have a quick release mount for the optic and backup iron sights on the rifle.