Pros
There is an incredible opportunity to lead other people at a young age while learning about a wide variety of topics. This career can change completely every two years depending on what your current billet is. The benefits are unsurpassed. Retirement at 20 years and full medical benefits for life. Tuition reimbursement, bonuses, life insurance, you name it, the US Navy gives it.
Cons
The work life balance does not exist. While on a ship, expect to be at sea more than half of the time. Deployments overseas last 6-8 months. Training to go overseas includes 1.5 month stints underway as well. When the ship is in port, working hours can be good (7-8 hours) or they can get bad (12-24 hours) While assigned to a shore command, you are likely to be called up to augment the US Army in Iraq or Afghanistan for a 9-15 month tour. The country is at war. I understand that there is no easy fix for that, but it is a large downside.