I have one somewhere. Cheap Mako or something, maybe that's the problem.
It increased my ability to shoot small groups/targets at longer ranges just as one would expect.
It also introduced significant parallax which I did not expect.
My opinion, a lot of weight and bulk, more lenses to keep clean, no faster than a traditional optic, less versatile than a low power variable.
If I only had one AR and it wore a red dot, I may very well still use it for load dev., as I have other options I prefer, it sits in a box somewhere.