Just received a vortex viper from Cameraland today and didn't have time to shoot with it yet. But I did get it mounted on my Knight vision and got to compare it with 6 other scopes of various sizes, quality, and price range. I compared light transmission and how easy it was to acquire a dark colored target with the crosshairs until 40 minutes past legal shooting light.

The scopes tested were as follows:

Leupold Vari-x III 3.5-10x40
Burris FFII 3-9x40
Burris FFII 4.5-14x42
Simmons 44mag 4-14x44
Weaver GrandSlam 4.75x40
BPS RedHead 2-7x32
Vortex Viper 2-7x32
and my Minox BV 8x42 Binoculars


Light transmission through all power ranges until 40 minutes past official sunset. Best to worst

Leupold
Vortex
Weaver
Burris 4.5-14
Burris 3-9
Redhead
Simmons

Best target acquisition. Pretty much which reticle was most visible at low light. Best to worst.

Weaver--By far the best.

Burris 4.5-14--All in the same category, but in this order.
Burris 3-9
Vortex
Leupold

Simmons--Horrible
Redhead--Left the game very early.

I do have 2 other Burris FFII's that I would rank higher than the Grandslam, but I didn't them out because I was running out of time. These are just my inferences in limited light conditions and don't necessarily reflect my preferences for value, warranty, longevity, or eye relief.

The Minox Binoculars are by far the clearest in low light conditions compared to the scopes

Great writeup. Let us know how it tracks after you shoot it.