I ended up getting one and running it on an SBR. I often drive under NODs with hunters running thermals on top - and this is a very good option for close in work on a small gun without much rail space.
I don't love the screws, it does have to be re-zeroed with some regularity (mine is not on a safe queen) and it isn't ideally shaped for SBR use. That said, the price is right, under NODs at close range it is the tits, and if I break it or lose it, I won't be heart-broken,
Mine has been rained on and done fine. I haven't dropped it in standing water. Yet.
Battery life: unsure, i keep extras and only run it when I need it. It lasted the season, so I'll toss that battery in the trash and start a fresh one next season.