I've been looking to get a simple 1st gen night vision monocular. I've been leaning twards ATN because of the name, but I'm not to sure about what features are important and which arean't. Any words of advise?

What is the end purpose you will be using it for? I've seen and used a few NOD's ranging from 1st generation up to my current PVS 14 3rd Gen unit. Next, what is your budget, and is there any way you can squeeze more out of it. I say this because the 1st Gen units are pretty tough to get much clarity, distance, and unless there are other light sources around, it's still going to be a green dark in the tube. With night vision, you really get what you pay for, and it's tough because the stuff that's worth it can be pricey. I'd say $1000 for a decent unit isn't unusual. My unit costs $3700. If 1st Gen is what you're going to be able to use, get something that uses common batteries like AA, make sure it has an IR illuminator, if used try to find out the tube life (These all conk out after so many hours.), and if at all possible, try it out somehow. If it's a dark cloudy night it may be tough to see much though. It can be that way with my good set too. It takes a different type of practice to get used to how to work with them.