I am just a hunter, not an optics or gear-testing expert. Comparing a V4 4-16x50 side-by-side to a V6 3-18x50, both set at the same actual magnification, I can get about 2-3 minutes of extra shooting time with the V6 at sunset. By that I mean I can see/distinguish antler tines for an extra 2-3 minutes while the sun sets and the woods grow dark with the V6 over the V4. In other words, to my eye, the V6 does have better light transmission over the V4. That's a small practical difference, though, and I am not sure if that slight difference matters to anyone, nor how that would translate to hog hunting at night. JMHO, and every ones' eyes are different.
I can say that I prefer the 3-18 magnification range of the V6 over the 4-16 range of the V4, but the V4 is still a very nice general purpose hunting scope.
