Overall the differences are small and when guys reports that a certain glass adds 15 minutes of time to their hunt, they were either selling a product or did the comparison at different times under different light conditions.
Perhaps this is most people's experience. I compared Swarvoski z5 5-25X52, Leupold VX-6 4-24X52, Bushnell 6500 4 1/2-30X50 side by side on deer antlers at 131 yards. They all went down at the same minute. Then on another day I compared the 6500 with the new Leupold VX-5 3-15X56. The VX-5 lasted six minutes longer than the 6500.
On another evening I compared a Swarovski z8i 2.3-18X56, Swarovski z6 5-30X50 and a Bushnell 6500 4 1/2-30X50 side by side. The z6 went down at 7:13PM, the 6500 went down at 7:24PM and the z8i lasted until 7:44PM. That means the z6 went down eleven minutes before the 6500 and the z8i lasted an additional twenty minutes. The owner of the two Swarovskis told me, "I knew that z6 wasn't very good."
The z6 and the first three z5's I bought proves beyond a doubt one doesn't get what one pays for.
