Your questions are a little too general. For shooting big game, 20X is more than enough. Just a couple of days ago I was sitting up on an ambush spot with a view of ranges from a couple hundred yards to about 1500 yds. So I decdided to do some "scoping" wiht my NF 5.5-22 set on different powers at different ranges. My conclusions.... 5.5x through the NF is more than adequate for deer size or bigger game @ 1000 yds.
Nightforce has great tracking capabilities, they are rugged, a bunch of elevation, holds zero forever, and reticles are designed for long range shooting. So if you are looking to shoot long distances constantly, then you need a scope that can take the abuse. -- gilmillan1
Nightforce is such a solid combo of reticle, available elevation, glass that is good enough to shoot at the longest range you can dial. Nightforce has bullet proof construction that can handle the incidental horse rolling or some other rodeo action. -- bigngreen
The total package. Nightforce is the best I have used as far as turret feel and solid detents. I have never had one that didn't track right on and always return to zero. Nightforce NXS is the best value for everything I need. -- Broz