Get yukon, I've seen MANY gen1 units, and yukon is by far the best on the market.
Absolutely crisp and clear picture, more crisp and clear than most gen2 models actually, just not as effective in dark conditions. And it's got an electric gate, so it will protect your tube if anyone shines a light at you.
ATN is crap, bottom of the barrel tubes. I was very disappointed in all the ATN models I've looked through.
Light sources change your range of focus, the IR light makes everything brighter up to "200 yards", which is actually more like 120 yards in practice.
And having light sources very close to the aperture actually reduces your depth of view. So for example, if you turn the built in IR light on while the optic is mounted to your weapon, it glares off your barrel or RIS, and you can only see about 20 feet infront of you.
However, if your driving as a passenger on the highway at night, and you put a pillow in the dash to block the glare of the road, the highbeams on the car allow you to see up to 400 feet away.
With good ambient light, say the moon is out, you can see 200 feet with excellent sharpness without any additional light sources. It's absolutely without a doubt better than not having NVD.
The yukon is a fantastic gen1 unit, you just have to know the tricks of using night vision.
And if you want some size comparisons for the yukon rifle optic;
