The higher the generation the better they work without an infrared illuminator. But, on a bright moonlit night 3rd or 4th gen looks washed out and 2nd gen looks alot better with or without an illuminator. Some of the better scopes allow you to dial the gain down and this will help. You have to look thru one with the illuminator off and then turned on to really see all the differences it makes. No good to have it on in the woods, you get alot of "feedback" from the limbs and leaves that are close. Biggest thing is that the animals eyes wont glow without infrared. This is a disadvantage because it is the glowing eyes that always let you know first if an animal is watching you. What you see thru a NV scope is no where near the detail of looking thru glass, remember it's an electronically generated image. Infrared illumination, if you have enough of it can make it hard to tell good quality 2nd gen from 3rd. The higher the gen number the better the resolution because they do generate an image with more dots per line. Kind of like a plasma tv...the 1080 looks sharper than the 720. The better the resolution the more magnafication you can run. But to answer your main question, you are always better off with good quality night vision for hunting at night even if the local laws dont allow the use of an illuminator. Many folks are a little misleading regarding the distances you can "see" with NV. Remember, "see" definately does not equal "shoot" or more importantly "hit." It's a matter of magnification mostly, most good quality NV scopes are around 4x-5x. Ever look at a fox coming straight at you at 500 yards with a 4x conventional scope???