Alright so my first impressions are it's an amazing piece of technology and really, really cool. That said it's a little underwhelming on a rifle, but that's because it's meant to be on a helmet imo.
Even in pitch black night, the Nox's black hot mode is like 90% of what a PVS14 sees, it's that good. Note I'm in a neighborhood and finding wildlife or any life to see was difficult. So what I wound up doing was walking around my property in black hot mode (just holding it up to my eye) and then when I saw something super black that could be an animal I would switch it to white hot mode to pick out exactly what it was. I was able to spot birds 75-100 yards away whether flying or sitting in trees. I spotted two bunnies about 100-150 yards away. They started as very black shapes and then after I made them white hot I could pick out more detail and see them doing bunny stuff. My dog in the yard was very obviously a dog and stood out against the background like a supernova.
On a rifle it wasn't quite as good but could work if that's all you have. First problem was (as shown in someone else's pic above) seeing your support hand/thumb, the gun's rails, and any lasers/attachments in the lower third of the picture. I tried it directly on the top rail first and had the same issue so then I grabbed a Unity riser afterward and put the Nox on it instead, worked way better and cleared the obstructions. Being this 2.26" height did actually feel great and it was just right. However, while I could see those bunnies I'm not confident in taking the shot with just the thermal view; that's where NVG has a big advantage imo, because you can go active with a laser/illum. That could just be my lack of experience shooting thermal though.
Maybe the biggest downside on a gun was just the display being so small. Once the Nox is supported and you're scanning around it makes me think a 5-9" external display mounted with it would really kick ass. This should be possible via the USB cable it uses to send data out, hmm.
I'm still undecided on if I'm keeping it, but that's not because anything is wrong with the Nox. The problem is I wanted the opposite use case, where it is awesome on a gun but I could walk around with it if I had to. The Nox is definitely meant to be on a helmet and alongside a PVS14 imo, if you are buying it to ride on a gun primarily you will probably be a little disappointed.
PS: Shout out to Huey Outdoors for getting it to me so quickly!