Not in anymore, but spent ~10 years in, back during the 80's.
Why did I choose the navy, versus other services? Well, I wanted something that would challenge me, intellectually, so I pretty much excluded the army & marine corp. That left the navy & air force.
Checking the air force, it seemed the only really challenging field they would have would be something having to do with electronics. While I like to fool around with electricity & electronics, I did NOT want to do that for a job (gotta think about the future, ya know??).
That left the navy. I talked to the recruiter, told him what I was interested in, and he had me take a practise asvab test. They give you 40 questions to do in 40 minutes......I took 1/2 that time, and aced it (and scored 90% or higher in every section of my asvab test when I took that later on). He told me the most challenging programs they had were electronics (nope!) and nuclear power. Hmmm......that sounded interesting! I took the NFQT (nuclear field qualification test) a few days later, and scored 72 out of 80, and this guy was practically salivating over the opportunity to get me signed up! :laugh:
So I did. When they told me they'd guarantee me whatever rating (job) in the nuclear power field that I wanted, I picked Machinist's Mate (mechanical field) over the other three, Electronics Technician ('nuff said), Electrician's Mate (electrical, no thanks) and Interior Communications (IC.....another type of electrician in the nuke world, though I don't think they have that rating anymore). Likely, I'm one of the very few people who's ever gone into that field with machinist's mate "A" (techinical) school guaranteed, and they thought maybe I was a bit nuts for going in that direction (they really wanted me to be an ET, but you know how I felt about that!!).
So the primary reason was the technical training. Can't hardly be beat, unless you go air force (and I heard recently that they're not guaranteeing ANY choice in what field you go into now, since they're so short-handed on certain ones). Also, the places you get to travel to are pretty wild, though I can't say where they're stopping these days, since I've been out for 16 years now. I will say that I work with a few air force guys, and just for grins we put up a world map, then stuck colored thumbtacks in it to represent where we had all served (each person their own color). Needless to say, my thumbtacks cover a LOT bigger area than any of theirs do, by far!!
Downside to navy? All that travel is while you're on deployment, which is usually maybe 5 days out of every 30 that you're in port. The other 25 is spent out at sea, usually making circles in the ocean, while you're loitering in an area, showing the navy presence to the "bad guys". The navy's a lot different now, in that they've gone co-ed on all the ships, so I guess the at-sea scenery is a lot better now! Oh yeah, and gaining rank in the navy is a LOT easier in the navy than the airforce, especially if you're in the ratings that have lower retention rates.
Hope that helps!