Pros
Officers are given lots of responsibility; even right out of college you will be in charge of at least 15-30 people who count on you to lead them, care for them, train them, and maintain equipment. Paid educational benefits are plentiful. The sense that you are doing something for your fellow citizens makes you feel good- there is a certain prestige with saying that you are an Army Captain. High commaraderie; I have made lifelong friends in the Army. Predictable promotions for doing your job are expected. The knowledge that if you have a serious life event, the Army will always be there to help you and your family. Seeing the world is certainly one of the more fun parts. I have been in the Army only four years and I have lived in San Antonio, Washington DC, Frankfurt, Germany, and the Middle East. You also get 30 days of paid leave a year. Although the pay isn't the best, they do give you appropriate allowances for housing and substanance depending on where you live. If you hang in there for 20 years your pension, healthcare, and benefits are in the bag!
Cons
It might cost your life. It could definitely cost your innocence. Living with those facts are difficult especially considering that families bear the burden of your decision to join. The Army does have a certain level of custody over every facet of your life. You also have very little control. Although career managers try to get you a choice location, job, or school, the needs of the Army always come first. Being that it is a government agency, there are Soldiers and Civilians alike that just do the minimum while competent, contienscious people do the lion's share of the work. Sometimes soldiers are placed in leadership positions when they clearly don't belong there. Lack of support from the public is difficult: a lot of people chose to lay into soliders about decisions made by elected officials THEY put into office! Pay is not commensurate with responsibility. Constantly uprooting the family is difficult.