SC,
Sorry, I just saw this post...
While I'm definitely not the final word on this, I'll throw in my two pennies on scopes used in a tactical/precision rifle role.
I feel if you are shooting PRS style precision rifle, with similar situations and distances, then you want a scope with magnification on the low end, around 4x-6x and on the high end of magnification of 20x-25x\ maybe 30x, tops. I think others covered over magnification issues, already i.e. mirage, narrow field of view, reticle obscuring of target, etc. Thing is, magnification only makes you more accurate, to a point. If you are shooting long distance or ELR, too much mag may hurt your focus due to heart rate, breathing movement, etc. Benchrest guys basically use sleds to hold their rifles, so can get away with higher magnification levels.
I have experience with NF, Vortex, S&B and US Optics glass. The two *I* prefer are NF and Vortex. Actually, Vortex is my current fav. S&B is hard to beat on all levels except for the price. I just feel the better value w/performance is NF or Vortex. I had a US Optics that would not hold a zero. Sent it back, had the turrets rebuilt, still had zero and tracking issues, FWIW. I sold it after the 3rd factory rebuild.
On that note, buying used glass can be a good deal with a company, like, Vortex. They offer an UNCONDITIONAL lifetime warranty, regardless of owner. I love this company and I run a Vortex Razor. Yes, I'm biased.
My last thought, which echos what the smart ppl have told me is to buy top quality glass. Do not skimp here.
I hope this helps some?