Most people who have shot both the NF and Leupold prefer the NF. Having used scopes that eclipse those choices in quality and features, it would be a wash for me and I'd probably take the cheaper one or the lighter one, depending on my use.
However, I warn that most people think they need a lot more magnification than they actually do to shoot at "long range." I normally use S&B 3-12x50 scopes to shoot as far as 1300 yards.
-z
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Practical Long-Range Rifle Shooting, Part I - Rifle & Equipment 
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Practical Long-Range Rifle Shooting, Part II - Optics
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Introduction to High-End Long-Range Rifle Scopes ("Don't Skimp on the Scope!")