This is the important point. By far the majority of moose I've shot or witnessed shot were killed with off hand shots. The rest were either from a kneeling position or leaned against a bush/tree/snowmachine. There is the odd circumstance or location where prone would work, but it's relatively rare. My sister bagged one from off her pack a few years ago, but that hasn't happened to me yet.
Moose is often more like hunting (extremely large) rabbits than anything. They guys I've hunted with that were consistently successful are able to thread bullets through trees and brush with no hesitation. Those that tend to be caught short messing with gear and setting up for a shot have been much less likely to put meat on the pole.
Putting shots on target trumps bullet style 10 out of 10 times.