I've owned both Nikon and Leupold glass over the years and never had a problem with either. Although, I believe the Leupold glass has a slightly sharper image. Admittedly, this point is arguable.
With that being said, I do own a pair of 10 x 42 Leupold Olympic binoculars. They are very rugged and hold up through a lot of abuse (or shall I say hard use.) The only thing I might change about them is the eye piece. I believe the design could use some improvement in that aspect. The eyeglass vs. non eyeglass wearer portion gets worn and gets to the point where it moves in and out too easily.
If I had it to do over again, I would've bought the Nikon's, but that is only provided they had a more robust eye piece than the Leupold's. The best way to compare is by visiting a sporting goods store and checking both of them out.
I have a system I use in Whitetail hunting during the rut that seems to work for me. When I make a mock scrape in the area I wish to hunt I will place a couple of 35mm
film canisters (film removed of course) in the scrape after I have cleared out all leaves and other debris. The film canisters are filled with cotton balls and saturated with doe in heat urine. This keeps the urine from soaking in the ground and can be refreshed on each trip if needed. I will also use the tarsal gland of the buck...