I tested some white and green phosphur NVIS side-by-side at a trade show. The rest of the NVIS were identical (same generation, same tech etc).
The difference is all about what you're looking at. If you look at an urban scene, the picture looks better on the white phosphor as it seems "right". Looking at a jungle scene, the greens win but virtue of the scene again looking "right". There may be differences in how your eye reacts to the colours but green was chosen in the first place for good reason (centre of the eyes response to light frequency).
The technology that really transforming using NVIS is not the colour but rather the rest of the goggle - tubes, battery location, stability, security and adjustment. If I had a choice the ANVIS 9 mount would win, but with auto-gating tubes - they are really next-level awesome. Being able to look at a bright light and see around it is definitively on my wishlist.