For low light? I can tell you from real world side by side comparison with a Leupold VX-5 3-15X56, Leupold VX-6 4-24X52, Swarovski z5 5-25X52 and a Bushnell 6500 Elite 4 1/2-30X50 the VX-5 lasted six minutes longer than them when "looking" at small deer antlers 131 yards away. I was stunned. I purchased all four of them so I had no axe to grind saying one was better than the other. They were laying on sandbags so they were quite still.
But a step up in price brings us to my friend's Swarovski z8i 2.3-18X56. It lasted another fourteen minutes over the VX-5!