I'm quite satified with mine. I was hiking last November in search of deer when I spotted one 550 yards away. I stalked closer and got within 400 yards, then 300 and then 240. The stalk began at sunset and ended with about 10 minutes of legal shooting light left.
I didn't get the deer but that was not due to inability to shoot in low light. I could see clearly enough to take the shot but due to the low light I could not tell if it was a buck or a doe so I chose not to fire. Having said that, I was prone and aiming at it at 400, 300 and 240 and the shooting would have worked but despite my hopes it never moved into position where I could determine antlers.
What I needed with me was good binoculars and not just my rangefinder.
