Pros
The money you get paid for housing and food doesn't get counted for tax purposes, you get to travel all over the world and when you're stationed overseas you have lots of opps to travel and see interesting things, there is opps for college and the college is accelerated so you can get through classes pretty quick, the physical exercise keeps you in shape, I forgot to mention that when you're overseas you meet all kinds of girls... No lie! European chicks rule!!! If you're smart you will have an oppurtunity to save huge amounts of money while you are in.
Cons
The Army is a classic example of those who work hard get more hard work. Maybe that's true everywhere but it is really bad in the Army. If you're the guy who "gets things done"... More things that need "doing" will come your way. Living in the barracks has it's drawbacks. Piss tests are a pain in the ass... I'm not pro-drug or anything like that; it's just that they start at like 4am and you have to drink tons of water in order to piss on demand. Stupid bosses are a real hassle... I know that it's universal but in the Army you can't just tell them off, you can get into trouble.