My agency got one for T&E and I liked it so much that I bought it. It is very versatile, especially when used with a magnifier. I also like the auto on as soon as I flip the covers down and the auto brightness seems to work very well. There has been one time that the brightness was not "perfect" but still workable and still much better than a fixed brightness. The time it was not "perfect" was on the range. We have some old spools that we use for barricades and I got down in a low kneel alongside it which placed me under some wood and in the shade. It was a bright sunny day and the target was out in the open. The dot was not as bright as I was used to on the other shooting stages but it still worked and was visible, just not "perfect" as it has been in every other situation I have used it in.
I am also working on a small annoyance with Millet on the tension of the adjustment wheel however it did not keep me from buying the optic as I like the versatility that no other dot has. What I have noticed is that under 5 shot rapid fire strings or more, the wheel has a tendency to back off making the dot size smaller. It isn't a problem at the middle and up sizes as the difference it moves is not noticeable but at the low end, it can move enough to turn off, especially when used with a magnifier as you can run it much smaller than with the naked eye. As soon as I know what Millete proposes for the fix, I'll be sure to post, but I am still please with what it has to offer.
It is also smaller and lighter than the SPOT I used to run. The factory scope covers work okay and if I didn't run a magnifier would probably not have switched them out. With the magnier I like that the Butler Creek cover folds out of the way more and they seem to lock closed tighter than the Millett's. I like this fact as it prolongs the battery life.
After trading emails with Millett, they suggested cleaning the grease off the adjustment knob/battery. They said it is greased from the factory to keep it from being too stiff. I did it and it is a lot tighter to move by hand, but by no means difficult. Unfortunately I did not get to the range today to see if it makes a difference while shooting.
I did get a chance to shoot it after de greasing as they said and it took a full 30 round mag before I could see any change in dot size. I cleaned it a second time with a degreaser and now it stays put.