Couple things here. First off is yes, I can see and use the range marks on the NSN sight very well. Next is it is not uncommon for someone to have trouble seeing them at first. Especially when folks try to do it for the first time, and especially if it is not mounted to a gun.
This is what I have noticed. Most importantly, keep both eyes open. If you close an eye, you may have a rough time seeing the reticle well. Next is, do not look into the scope, or focus on the reticle. This will also make it very blurry. What I tell people is to keep both eyes open and look right past the optic. Look at your target area. When you do this, the reticle comes in sharp and clear and is VERY easy to use. Granted I have good vision and my eyes arent as old as some, but its a snap for me and I love it.
Last thing is... if you are shooting at silouette type targets, or... two legged pests (what the optic was designed to be used to shoot!) the reticle will in fact help you determine the range you are shooting at. You will notice each one of the cross hairs is a different width. The 100 meter cross hair has two fat bars on either end. An average human torso will fit inside these two bars at 100 meters. The 200 meters cross hair is slightly shorter left to right. Thats because a human torso will fit inside that line at 200 meters. The 300 meter cross hair is shorter still. Thats because a human torso will fit inbetween that line at 300 meters. This is true all the way down to 600.
So, not only will the different cross hairs let you know how much you have to hold over, they will help you determine the range at which your target is to begin with. Very good and very useful design.