I have a Zeiss and can range to 1400 in good conditions, and 1275 in any conditions. I went out with my friend and his G7 yesterday (and many times before) in mountainous terrain and bright daylight, and he was not able to range any further than I was with my Zeiss. I watched him put a brand new battery in it and that didn't help at all. In fact, he typically had to make many more attempts to get a reading on the same target (rocks) than I did. Our readings did match to the yard on a variety of targets, but this was all cross canyon ranging where beam divergence isn't as much of an issue.
I was with this same guy last winter and we had two coyotes standing on a snow covered field at about 800 yards for 10 minutes, and try as we might, could never get a range on them with his G7.
I was leaning heavily (i.e. reaching for my wallet) toward buying one, but the failure to range adequately has held me back. I inquired of Gunwerks whether they would agree to refund my purchase if I buy one and it doesn't range for me as advertised, which I'm taking to mean 1500 yards all day long, and 2000 yards under the best of conditions. They have apparently declined that request by responding to a portion of my email but twice ignoring that part.
So at least for now, I think I'll leave my credit card in my wallet and stick with what I have until something better comes along.