I have been shooting the Nockturnals since they first came out - I still have about 3doz of them.
The only ones that have ever failed on me are the ones that I robin hooded with another arrow.
As far as the color - I agree that it is part how you perceive color and part the lighting conditions at the time of the shot.
Also background effects etc.
The bummer is:
Colorado considers them an electronic device - hence - illegal to use for hunting!