My buddy hooked me up with a demo model NXS 3.5-15x50 last season they had. Because it was a demo, I picked it up for around the price one would pay for vortex viper. The NXS line is amazing. They have glass etched reticles, the dials are perfect in every way, highly repeatable. The zero stop system works as described, you set it and forget it. You can always return your scope to zero after dialing. The glass on the scope transmits so much light its ridiculous. As twilight sets in i have to start checking my watch. I can still see the field Im hunting in good (not great) detail through the scope long after the 30 minutes after sundown has been reached and for that reason, I have to watch my time. With other brand scopes, I would get down out of the stand when I could no longer see detail enough to be ethical in the scope. Not so with the night force NXS. The major drawback to the NXS is weight. The night force scopes are about 25% heavier in many cases because they are built like tanks. I went with a 32mm objective to reduce weight, but a standard 1 inch tube burris 3-9x40 weighs 13 ounces. The new night force, which is a 30mm and not a 1 inch, will weigh 19 ounces even though it has a smaller bell. Nightforce has a new line out called SHV. The SHV line is a good bit cheaper priced. It has the exact same glass as the military grade NXS but is not built like a tank and will lack a few features. For example most of the SHV line has capped turrets instead of exposed zero stop and few have illumination. I highly recommend Nightforce. Highly. But they are expensive. With that said, I have owned dozens of scopes. My favorites are Nightforce, Vortex, and Leupold and in that order. I would not hesitate to buy a Vortex Viper. Great scopes, great company, and great glass packed with features. Not very far from the night force quality and every bit the quality of a comparably priced leupold.