My logic from years ago.
The Vietnam war was heavily under way when I decided to join.
Army and Marines. You get to carry everything on your back while assorted people shoot at you in some of the worst terrain ever invented.
Air Force. Nice organization, nice facilities, and nice people. Only problem with their vehicles is that when they sink they are usually a long way above sea level and they sink fast.
Navy. Everything you own goes with you along with color television, hot showers, good food, movies, and if you start to sink you are already at sea level.
If you are just in for four years you will probably be a grunt of some kind no matter what you join.