The Fixed Nikon Monarch should be less than a Fixed Leupold VX-III. The new VX-IIIs are awesome (I have a 3.5x-10x-40mm version) and I love it. It is expensive for it's class. I can get a Monarch for about $150 cheaper and the Monarch is almost as good.
I own several Nikon Monarchs and I have been very happy with all of them. However, if you don't mind spending the extra money, then get the leupold.
The Buckmaster will be the least expensive scope, but it still has very good optics. I consider it the best value of the bunch.
Zachary