I had one on top of a Nightforce scope for a while as a backup with an offset Larue mount. Worked fine, but it is fragile -- you drop the rifle on it, or hit something hard on its top, it can shatter. I have seen a mount that put a metal cover over it (maybe also by Larue), which is what I would recommend if you went with this sight.
I have two and they are fine. I haven't dropped one though. The only thing I do not care for is the dot seems to blink at night at darkest conditions. Other than that they hold zero and do what they advertise.