As a young woman, I'd say not to join the Marine Corps. Girlie girls would never make it, if you're not used to the attention you get from being one girl out of hundreds of male counterparts, then don't join. Statistically we're more liable to get hurt, killed or ***** than any other branch. But if you want to be part of the only fraternity that accepts woman and be more fewer and prouder... then the Marine Corps is the branch for you - which is why I decided to join.
With THAT out the way - best branch overall is the Air Force - girl or guy wise. They get the best of everything and move up in ranks fairly quickly and easily. Then Navy - great ship & shore destinations - also good benefits. Then Army is good for scholarships and whatnot. All these branches have plenty of room to move up in rank, good health care and good job placements - so long as you do well in the ASVAB. And then, of course, the Marines...
...if you like to get the bottom of the barrel from all the other service leftovers...like to pop Motrin for all the pain you're gonna be in because we only get Corpman - not real doctors, like eating green eggs and ham for breakfast - literally - because we don't have "dining halls" and usually only get a few minutes here or there to eat, like to clean and buff floors every night because you ARE your own cleaning crew, don't mind NOT getting promoted for 2 years at a time because your MOS field is closed, and don't mind sleeping in a tent near a bush, in the middle of the desert in 20 degree weather in the morning with temperatures soaring to 100 degrees at night with nothing but a rifle, a pack of cards in your cargo pocket and a canteen full of stale tasting water... it's just the right place for you! BUT with all that, the actual pluses are... kicking ass and taking names McGuyver style, the damn nice dress blues that everyone in the world recognizes, protecting government officials because no other branch can and would want to do the job and retaining the title Marine for the rest of your life. The job's not for everyone. So depending on your choice, or for me, the high road I decided to choose for myself and the things I wanted to experience and learn with the toughest branch I could find - there's a place in the service for everyone.