The Night Vision Scope provides high contrast outlines to nearby objects and illuminates nearby soldiers and vehicles.
Sight attachment illuminates the white aura around targets, making it easier to see hostiles in low-light situations. With this sight, cloaked Infiltrators and Flashes with Wraith Cloaking Device are totally invisible (they are fully invisible, and will not pick up until they are shot) in comparison to the slight cloaking haze effect when viewed with naked eye.
Targets begin to get darker around 50 meters and are not visible at all past 130 meters(100 and 190 meters for DV6), meaning this attachment is only suitable for close to medium range engagements. Distant targets will not be illuminated. It is also important to note when using this scope that:
You cannot see your own tracers (or your own muzzle flash)
You limit your Field Of Vision
Scope sways slightly side to side (like a high zoom scopes)
When playing on low graphical settings you get the benefits of HS/NV. (Targets stick out, particle effects don't obscure vision because they're turned off, etc.) When using NV scopes on low settings you also get less range (things blur out closer). Making it much less useful than on high settings.
The NV scopes takes longer to "activate" when you ADS by almost twice as long when compared to other reflex sights.
NV scopes does have some benefits, the ability to see through smoke/explosions is very useful in high intensity firefights and target acquisition is very easy because of the high contrast visuals.
This sight can be very effective on short range guns, such as SMGs and shotguns, where the iron sights' ineffective range is around where the gun's ineffective range is to.