Nikon has discontinue the 6x42 Monarch so the Leupold is the best. I have both the 6x42 Nikon and Leupold and the 6x36 Leupold and there isn't a whole lot of difference in the three. Go with which ever you can get the best deal on.
A Doe walks out of the woods today and says, that is the last time I'm going to do that for Two Bucks.
