BigJohn, I don't have one and I haven't used one but I have a buddy who has one one and I think the Gunwerks guys frequently pair it with their long range custom guns. The thing that is different about this than the typical range finder or even one that is built into binos is that it takes temp and barometric pressure readings. IMO this is especially important when shooting to ranges greater than 600 yards. I personally think it is a little overkill for the average guy, but for those doing long range it sounds awesome.