What are some of the reasons you guys favor one branch over the others?
My cousins are all enlisted in different branches and it's hard to get unbiased info out of them, so any help is appreciated!
I favor the Army because I come from the Army, so it will also be hard to get unbiased views from me, but I can tell you why I favor it.
The Army does not force new physicians into general medical officer (GMO) positions, essentially serving an intern year and then going off to be a GMO somewhere before being able to finish your residency. Some people like the GMO idea, as it can put you in interesting places (dive medical officer for a SEAL team, for one). Others hate it, because it can significantly interfere with career progression.
The Air Force takes the best care of its people, in terms of quality of life, bar none.
The Navy has the most hierarchical rank structure of the three. Hard to explain until you've experienced it, but there is a much more pronounced difference between officers and enlisted, and between senior and junior enlisted, in the Navy than in the other services. For example, there are passageways on ships that only officers can walk through, or that only senior enlisted can walk through. I always liked the Army's philosophy in this regard, that if the men are sucking, the officers should be sucking worse.
The Navy can put you on a ship and send you to the Mediterranean, the Persian Gulf, Singapore, Thailand, and pretty much any other awesome place you can imagine. The Army will put you on a huge plane and fly you to Germany, and maybe on to Afghanistan. Yes, there are cool postings in the Army, but not as easy to find.
In the Navy, you will occasionally have to deal with Marines, and Marines are weird. Enough said.
Hope that was helpful, there are other threads on here (military medicine) where the question of which service is delved into more thoroughly, and probably better.