Pros
Can be interesting. Serving our Nation. Very secure, very hard to get fired, promotion is automatic for first two promotions. Unbeatable benefits. 100% medical and dental. Commisary(Highly discounted grocery stores), Navy exchange(Highly discounted Wal-mart essentially). Retirement after 20 with pension for life. Bonuses given based on specialty.
Cons
Spending time at sea, away from family 24-7 while at sea. Rigid, old-fashioned, leadership structure with little room for creativity. Ridiculus amounts of red-tape, needless paperwork, inspections and exams. Work-life balance not healthy. You are expected to work late past published working hours. Overly conservative, non-progressive culture. Navy is very slow to change its ways given how old the organization is and how steeped in tradition it is.