Depends on ur time to hunt, and terrain. If ur only hunting 1-2 days then i would say the 10x42 binos and compact spotting scope would be fine. If ur blessed to have 7 or more days, than i would suggest the 15x56 and bigger optics/more weight. Seeing at greater distance is always the advantage, but say, if I see a trophy mule deer at 2.5+ miles across a canyon with my 15x56 Swaros and STS 80 HD spotting scope, it would be all useless and fruitless to attempt to trex after the animal, and relocate a back country campsite if I had no time. Always match your bowhunting with whatever availiable time you are given, thats what will increase your odds for success.