Best value for long range - Vortex Viper PST 6-24x50mm FFP Riflescope

I have had this scope on my .338 Lapua mag rifle for almost two years. The zero has not moved since I mounted it (with a +20 m.o.a. base and Burris Xtreme rings). The elevation and windage turrets are solid and turn with very positive clicks which are easy to count. The spacer system to set up the positive return to zero is easy to set up and works well but doesn't provide an absolute return to zero, only to a few clicks away.
I particularly like and highly recommend the FFP reticle which changes in size with zoom setting so that the reticle subtensions remain constant regardless of zoom setting. This is of particular importance when using the reticle to estimate range as it doesn't need to be set to a specific zoom setting to be accurate.
The optical quality is impressive. I have used Nightforce and Leupold scopes of similar power and I just don't see any significant difference. Certainly not enough to justify the difference in price. Overall, this is a terrific scope for the money and ideal for shooting at 600 yards and well beyond.