Avantages
Teaches you a trade while paying you. Social appreciation. Purpose. If you have no idea what you want to do with your life especially as far as a career goes, run to a recruiter. Regardless of whereever you come from a military career is your stepping stone into middle class and up living and career opportunity.
Inconvénients
Every extra dollar you attempt to make beyond your rank will require more work than you will be paid to do. The real payoff monetarily you get from competing in the military will come in to play during your post life. Confidence, courage, accountability, etc are not standard attributes in people at all.