It may have been on the Midway USA sight, I don't 100% remember. But on there, I think people can write reviews of products. The regular ATn sights eemed to be okay, but there was a lot of neg comments about the digital one. Plus, I read a lot of neg stuff about them on Ar15 last Dec. So, I just went ahead and got an Eotech.
That's all I know about them. But, I too was initially interested. As a whole, on a lot of sights, I see a lot of neg stuff about ATN quality.
I had it slide mounted on my Glock 20 since Dokter Optics was kind of MIA at the time, and before I even got around to using it the mount for that application was recalled, but I decided I'd give it a shot anyway and it was a total failure, there was simply no way the screws would ever stay tight with the forces involved with that sight being slide mounted, even more so on a 10mm, also it switched off because of the battery being jarred from the recoil, but that was an easy fix as was mentioned.
Later I milled down the standard bracket it came with to fit into the rear sight grove of the PS90 and have been happy with it in that use so far, it has a nice field of view, the housing is slim and doesn't block vision much, gives me a good cheek weld and it has three recticle patterns. Is it as well built as Eeotech/Aimpoints?.. no, but it's much cheaper.
I think it'd be well suited for some people. I probably wouldn't have it on my PS90 if I didn't already have it since I get the feeling I'd be much more happy with a 2X sight of some kind on it.