So, I never really thought about getting the Night Person perk under Perception because getting an extra +2 / +3 INT and PER between 6pm and 6am (night time) never really seemed that useful. I snipe with the unaided non-VATS eyeball, so PER doesn't really do much for me and whatever extra little experience I get from a few more INT points hardly seems worth investing a perk point.
That said, the rank 2 perk has the added "benefit" of letting you see at night. At first I was worried it would be a "nightvision" kind of sight and I can't really see anything in that kind of view. So I saved up two perk points and intended to buy both ranks at once, try out the vision, and if I did not like it, load an earlier save.
Well, the good news is that the vision change is pretty clear --- it basically just makes it look like "daytime", without any green tinting or anything. It only works when sneaking, but then I'm almost always sneaking (especially at night) anyway.
The reason for this post / warning is that as handy as it can be to be able to see in dark places, there is a down side that I did not realize until later. While your view is not tinged green or anything, the simple brightness that pervades EVERYTHING tends to "wash out" the view. When I stood up from my crouch, and the night vision shut off, I realized how much more vibrant and colorful everything was, with the deep shadows and the flickering lights and so on.
Without using console commands, there's no way to get rid of a perk, so I'll live with it on this (first) play-through but in subsequent ones I'll be skipping this perk entirely. As useful as it is to be able to see clearly in the dark, it's too much of a sacrifice to lose the color and vibrancy and light/shadow interplay. If it were possible to have that quality of vision though, say, a modded set of Welders Goggles or Wrap-around Shades where i could toggle it on and off (like a Pip Boy light that would not, of course, alert anyone).... then that would be fine. But this perk? Buyer Beware.