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.
If you're lucky enough to be on private land and can leave your stand up during the off season you can tie an old piece of cloth or something of the sort to your stand. I like to use an old camo bandana that I have. That way the deer get used to the movement and eventually don't bother even looking up when there is slight movement. This may just give you the time to draw your bow or raise your gun without being detected.