I have own and compared the NF, Vortex Viper PST
, and Leupold Mark4 at dusk. The NF won hands down. The Mark4 edged out the PST by a little bit. Now which one would I get. I would get the PST viper. Only because of the cost.
NF 5.5-22X56 $1600
Mark4 6.5-20X50 $1300
Viper PST 4-16X50 SFP $700