Pros
The retirement money is good, 20 years goes by quickly when you have fun. Overall, it is fun. There is a certain amount of prestige in some circles as a soldier. Where else can you do a few different jobs that people have made video games about? You wont ever see "Bank Teller Simulator" from microsoft!!! The Army has several family and community oriented programs which are great if you get into that sort of thing. You get 30 days of paid leave per year, and several 3 and 4 day weekends per year, provided you don't get stuck on some last minute, ill-conceived and planned work detail.
Cons
Long hours, frequent deployments, frequent moving. Have spent a lot of time living in poor conditions. People getting promoted and recognized when they clearly did not accomplish anything. Discipline level is not what it used to be. Young, inexperienced leaders, some of whom are incapable, but still stumble forward. The mentality that everyone is capable of increased leadership and responsibility, which leads to everyone eventually moving up in the ranks, regardless of their ability or desires. Travel, field training, weapons and vehicles all used to be exciting as a young adult, but the older you get, the less 'cool' all of that is. The army has a way of taking the fun out of some cool things sometimes. Oh, and the false motivation gets old, can anyone say "Hooah"?