Pros
The work is hard, the play is hard, and the pay is consistent. You usually know what is expected with few exceptions and for the most part you are part of small and large teams working together towards a common goal. The travel opportunities are great. Go in single, don't force a spouse to endure the hardships of Navy life along with married life - it is a heck of a strain. Where else can you retire at 40-45 with pay and still have a life?
Cons
If you are on board a ship it is not like Mama's house. You are going to have to carry your own weight or suffer the consequences. Slackers are not well tolerated, and sometime find themselves on the end of a very raw stick. There is no place to run, and not many to hide - you must be able to live and work in very close quarters 24/7/365. Low paygrades suck no matter whether an officer or enlisted, so be prepared to take a lot of crap for awhile. For wannabe officers: Just cause you've got a commission doesn't mean you well get respect, much less a salute.