Oh, boy, good subject!
I'm active duty military, and the military is currently paying for my master's degree. There are lots of great options out there in today's military -- more than most people imagine. The important things is to do your homework. Check out what all the services offer, and consider what programs best meet your interests and needs -- both long- and short term. I've known many of soldiers who, with hindsight, wished they'd taken a bonus over a college fund, or vice versa, as their life goals have changed.
Going into the military is an adjustment -- it is a different culture. People are people everywhere -- but the military has its own language and way of doing things. Basic training/boot camp is designed to turn a civilian into a military member, and I guarantee it will be the toughest thing you've ever done in your life (until you go do something harder in the service ...). You'll meet lots of great people, and so long as you keep things in perspective, can have a great time. You -- not the military -- define your level of success and potential.
As to choosing services and programs:
First, there are as many horror stories out there as there are good stories, and some of both are even true. Most people in the military don't know how the recruiting system works. Most recruiters have a primary specialty in something else, and are sent off to recruit for a couple of years, in what is essentially a sales job. The system, more than the recruiter, has a great deal of say in what a potential applicant receives. The applicant has the ultimate control of the process -- only you can say yes or no, and sign your name.
How do I know? I've been a recruiter, and I've supervised recruiters. (Those who hate recruiters may cuss me out now, privately.) There are more good ones than bad, but there are occasionally bad ones. Don't let it worry you. But like anything being sold -- if it sounds too good to be true, it may be. Much service information is not false, or even deliberately misleading, but can be confusing.
For example -- your choice of job skill (MOS) is determined by a guidance counselor at the Military Entrance Processing Station (MEPS) -- not your recruiter. You will be shown a number of possible jobs, based upon your scores, your physical limitations, and the available positions. The services have needs, and will try and fill those first. You might want to be an in-flight missile repairman, and the service may have that job, and you may even qualify -- but you won't see it unless there is a training seat available (and available seats change on a daily, even hourly basis). The guidance counselor may want to put you in another job, like left-handed wrench repair, instead, since that's what the service needs. Most of the incentives out there -- short enlistments, college funds, bonuses, station of choice, etc -- are designed to fill those critical MOS skills. Be flexible -- if all you want to join the military for is to be an inflight missile repairman, tell them that up front, and insist. But if what you really want to do is see the world and get a little extra cash, tell them that and keep an open mind -- there are a lot of options that could fit those needs.
The service will give you what is in your contract. Read it carefully, and understand it. Some services offer open contracts with respect to MOS; others retain the right to change your MOS if you fail to qualify for you're original MOS -- based on the needs of the service. When I was in recruiting, the percentage of recruits that received a specific MOS in their contract (and this may have changed in four years) was roughly: Army 100%, Navy 85%, Air Force 50% (the AF often assigns "job fields", rather than specific MOS), Marines 15% (you join the Corps to be a Marine first, MOS second).
All of the services have great programs that could meet your needs and interests -- figure out what you want from the experience (not necessarily $$ or specific rank -- those are like power windows and sunroofs, to use a car analogy) and find the service and program that can give that to you.
I'd be happy to answer other questions here.
Good luck!