I had an old Nikon Yardage Pro. It worked great from about 7:30Am to 4:30Pm but in the first morning light and last light at night it was not dependable. So lastyear I bought the Bushnell 1500 Arc model. I live in PA but travel out west to hunt and judging yarage out there is tough without the rangefinder for me. This thing works reliably in low light conditions. I went with the 1500 because as RR said, the effective range on deer size animals is about 1/2 the published range if you read the fine print. Their max ranges are tested with a reflective white test board, i.e. ideal conditions. We all know how many white deer are out there. Good luck on your purchase!