Free college / work experience.
If you score highly on the test you can be placed in certain postitions that guarantee high level pay and employment once you leave the military.
State and federal jobs ALWAYS hire veterans first and they are some of the best / highest paying jobs you can get.
Good physical fitness and a way to gain discipline.
Way to join an elite club that you will always be a part of until you die.
I know LOTS of people who have been in the military and they never saw combat. They have amazing jobs and are physically and mentally fit.
Downsides: chance of being deployed in a combat zone and all the horrible things that can occur as a result of that type of trauma.