I had several problems with the IronDot. One was that the rear sight would not stay on. The end of the sight nearest to the muzzle was suspended in the air, without wedging into anything to keep it in place. I did put some plastic shims under the sight that held it in place for a few mags, but then it flew off.
Also, while the magnets do a good job of keeping it from flying up, there is still quite a bit of play in the whole device. I had gotten it sighted in and then noticed that the dot was not aligned with my front post. I could grab the body near the switch and wiggle it side to side, enough that maintaining a zero was not possible. Maybe this problem was made worse by the problem mentioned earlier with the replacement rear sight.
The bottom line was what good is a sight if it doesn't hold zero or stay on the weapon. I've read many other people that were perfectly happy with it, but that was not the case for me.