>131019
Militaries mainly use calisthenics because it's convenient for training a large group of people. Unless your goals are to develop skill at certain calisthenics movements (e.g. pistols, which require a lot more balance than most exercises using weights) I think your results will be significantly better with that gym membership.
Sprints and weighted dips/chins will always be worth doing, but pistols and the like don't actually translate well to regular squats. I learned this from experience when I spent a year doing solely unilateral movements for legs. It's hard to replace deadlifts for lower back and grip strength. Trust me, OP, there is no replacement for squats and deadlifts, and having a large portion of your muscles working at the same time works wonders for overall fitness. That said, you could probably get away with doing calisthenics for every other muscle group if you had a pull-up bar and a basic dumbbell kit.