No side by side first hand knowledge but the 940nm is less visible to animals or humans looking at it, more stealth. It is also said to be shorter range but I haven't had any issues with mine at the yardages I use it at, say 200 yds or less. Haven't really tested it further I have an 850 and yes, you can see a faint red light. But considering I've shot racoons, coyotes, and rabbits using a straight red lensed flashlight attached to my scope without any issues I don't think the red glow of the 850 will matter. Yes, I've had animals look at it for a second, but then they go about their business. This is for both urban, conditioned animals and rural run at any hint of human animals.