Pros
Early leadership experience, challenging and exciting assignments, important work for the nation, good compensation, superb travel opportunities. The Navy trains you very well for every position and then gives you more authority and responsibility at an early age than you can get anywhere else. The leadership skills your learn also instill confidence in you so that you are comfortable in any situtation. You learn how to handle stress, manage time, and delegate responsibilities in a team environment that produces real results. The technical training is superb and sets the standard for the military. The Navy's focus on detailed understanding is far superior to that I have observed in other services. Finally the comaraderie in the Navy is execellent. On a ship we really operate closely together and are a very tightly knit group.
Cons
Time away from family, seasickness and the fact that you must leave after 30 years of service. Compensation is targeted, despite changes in recent years, around retaining the right numbers of personnel of the right seniority rather than based on performance. Two officers of equal rank are paid the same regardless of performance. The higher performer may be promoted earlier, but he or she may not be depending on individual circumstances. Over a career this usually works out to ensure the best rise to the top, but there are always cases that make one wonder "what are we doing" when we promote some individuals over others.