Which branch of the military should I join?

(Join to see) Since I served in the Navy and the Army, served with the Marines (actually, I drove them around), and flew all over in Air Force planes, I strongly urge you to seriously investigate the Coast Guard, from whence I retired. I'll forgive you this one time for not picturing it or mentioning it. But, if you want to receive every benefit you can receive in those OTHER outfits, including rank, pay, medical, retirement, BUT have greater advancement opportunities in a military service with ELEVEN federally-mandated missions versus basically one or two for the others, then give the USCG an honest and thorough look. Fifteen years after I joined the Navy I found a wonderful home and even better family in the Coast Guard. Best thing I ever did, military-related. No matter where you are, I can help open doors with a few phone calls. Ball's in your court, but, please do not overlook the USCG. It has everything you asked for and much, much more.

Why are you discounting the Air Force? I started out in the Army and moved to the AF. As far as being deployed, the AF has actively been at war since 1991 (the first Gulf War) as we never left Iraq after that war.
Picking which service depends on what you want to do in the military? Since you have are an Engineering student, is that what you want to do? AF REDHORSE and CE units deploy all over the world for both military and humanitarian reasons.

Also, do you want to be enlisted or officer?

You are on the right path though, talk to as many folks as you can before you make your decision.

I suppose it depends on what you want to do. All four services deploy all over the world for various crisis in various capacities. As for advancement, that is almost an impossible question to answer, as those metrics change all of the time. It depends on the needs of whatever service is at the moment and what career field you are in as well as specific metrics that each service has for promotion. Also you are more likely to excel in a career field that you really want to be in. I have seen some people chose career paths for the advancement opportunities, but when they got there, they hated their jobs and did not really excel, so keep that in mind.

What you should do is talk to each of the ROTC unit admissions officers and find out which jobs appeal to you the most and meet whatever goals you have. You might find the job you want may not be in the service you envision.

From the sounds of your engineering pursuits, you might look at the Army Engineer's branch or the Air Force Civil Engineering career field. They deploy all the time for humanitarian missions.

If I had asked this question in 1996 (when I decided to go to West Point), I'm certain the answers I would have received would have in no way predicted what each Service would have been doing over the next 20 years. No one has any clue what next year or the next few years look like, nor does anyone have any clue what each Service will be doing and will look like in 5 or 10 or 15 years. There are just too many variables. Here are my thoughts on the questions you’ve asked:

Which Service has the best chance of being deployed? This is the wrong question. If deploying overseas is one of your major goals in life, the military isn’t a bad option. However, if you really want to spend most of your life overseas, you should look at other options, too. Bluntly, the vast majority of the military is based and remains in the United States. Other options--say, becoming a Foreign Service Officer for the Department of State, joining the Peace Corps--almost guarantee service overseas. With the military, its more of a crapshoot. For example, you can still find--after 15 years of consistent conflict--a large number of people in the U.S. military who have never left the continental United States, who have never deployed, etc. Some of this is on the individual; some of it is just random chance and bad (or good) luck (depending on your perspective). A better question to ask is: What career fields across the Services have the best chance of deploying and being stationed overseas? I can’t really speak for the other Services, but for the Army, I would guess that for career fields open to newly commissioned officers, all of them have about the same chance. Its not until at least one becomes a senior 1LT that one can branch out into career fields with larger chances--like SF and Civil Affairs. And its not until one is a senior captain (or so) that one can volunteer for career fields (say, Foreign Area Officer) where the majority of jobs are overseas. But again, even this question is the wrong question to ask, as none of the Services really care about what you want to do or your desires. In almost all pre-commissioning programs, you will be assigned a career field based on where you are on the order-of-merit list. If you’re near the top, you’ll likely get your choice. If you’re in the middle or at the bottom, the Service will choose for you. Thus, perhaps an even better question to ask is: do I want to serve in the military, regardless of the career field and regardless of the opportunities to serve overseas? If yes, then, for the Army, at least, pick a combat arms branch from which you can volunteer to transition to SF. If everything works out (and this is a big if), you’ll end up in a career field that deploys all the time.

Which Service has the best discipline? I think even Airmen would argue that the Air Force isn’t competitive here, so that leaves the Navy, Army, and Marines. The Marines will always argue they are the most disciplined, without providing any real evidence (as is the Marine Corps tendency--look at their gender integration study as an example). Again, though, this may be the wrong question. In all Services, certain career fields are “more disciplined” than others. You’d need to be able to recognize the difference in what each career field and Service thinks “discipline” means, though. I’d suspect that each Service has components that believe they are the most disciplined. This generally relates to the core functions of that Service. In the Army, the infantry likely thinks it is the most disciplined. Same for the Marines. For the Air Force, pilots. For the Navy, surface warfare officers. This, of course, excludes all of the special operations career fields, which one really can’t join until after serving for a few years.

Which Service has the most room for advancement? Really, all Services are equal, because DOPMA applies to all Services. However, each Service implements DOPMA slightly differently. If your question is “In which Service will I be promoted the quickest?”, the answer is the Air Force. Air Force promotion timelines are currently about two years ahead of the other Services (once you get past the junior officer ranks)---senior majors (those with 15 or 16 years in Service) in the Army are currently subordinate to junior lieutenant colonels in the Air Force (those with 15 or 16 years of Service), simply because the Air Force chooses to promote at a faster rate. Making lieutenant colonel is equivalent to earning tenure; make lieutenant colonel, you can serve up to 28 years. Top out at major, face mandatory separation at 18 years. DOPMA also establishes target promotion rates for each rank. RAND has a good DOPMA site: http://dopma-ropma.rand.org/. Its good to understand DOPMA, as it explains officer career management.

What are you most interested in doing, leading troops or operating equipment? While in all Services officers lead formations, how this is done varies greatly. In the Army, an officer’s core task is to lead troops. Same in the Marines. In the Navy, officers lead troops but also are primary equipment operators. In the Air Force, officers lead, but not until much later in their careers. For example, the first command in the Air Force is at the lieutenant colonel level. In the Army, the first command is at the captain level. The Marines consider their first commands to be at the 2nd LT level (ie, “platoon commander”).

Finally, your undergraduate major is essentially irrelevant for your service in the military, unless you get lucky and branch (or get branched into) a career field that is highly relevant. You say you’re an engineering student; that’s great, but the only really relevant thing you’ll take away from that is the engineering problem-solving method, which is highly relevant for military service. Unless you pursue it and get lucky, the chances of you using your engineering skills in the military are quite slim; even if you branch Engineers, at least early on. The most important thing you can do for an undergraduate degree--for the military, at least--is achieve a high grade point average, so that you can use that to help your chances of getting into a quality masters program later on.

As for me, I’m an Army Foreign Area Officer, but spent my first 8 years as an infantry officer.

Disclaimers:
1. I'm not an officer
2. I was Navy (still am, I guess)
3. I was a nuke on subs.

The technical knowledge and skills you will learn as a Navy Nuclear program student are unmatched by any other service. Hands down. Your training will take at least 18 months of book and hands-on learning. And then you'll get MORE in the fleet.

If you don't volunteer for subs, you are GUARANTEED to deploy to exotic (and dangerous) places... a LOT. There's a reason they say "Join the Navy... See the World". Submarines? Not so much...

You will be leading some of the most intelligent (and independent) men and women in uniform operating the most complicated engineering marvel man has ever created.

If you go subs (and are one of the best of the best of the best), you can be in command of one of the most powerful and adaptable weapon platforms on earth as a CDR (O-5).

When (if) you get out, you have a 98% chance of a civilian career making a 6-figure salary within 3-4 years.

If you "are" an engineer (rather than just an engineering student), you will get this last point... You get to push the most powerful warships ever built by man as you wrest control of one of the fundamental building blocks of the universe itself... and get paid to do it!!! Mwah ha ha ha!!!!

(I could do SO MUCH MORE if I only had minions... which, as an officer... YOU WILL!!! MWAH HA HA HA HA!!!!)

Remember, Leon, I admitted my bias in the beginning.

If you want to do what you studied for... I would suggest either the Seabees or the US Army Corps of Engineers. Don't let the Navy lie to you and tell you to be a nuke engineer... you WON'T be doing the kind of things you have studied for. Both Seabees or the Army Corps of Engineers have better chances for humanitarian missions... but if that is what you want to do, have you considered the Peace Corps?

Marines have the best discipline and the SPECOPS/SF guys have good discipline but in their own way... room for advancement? Well that I do not know right now... you would have to check CREO groups for Navy stuff... that tells you what is overmanned and what has shortages... other branches, I don't know.

For travel? Navy. For education? Air Force. For bragging rights? Marines. For a good quality of life without having to shamefully say you're in the Air Force? The Army ;)

Like others have said, he really depends on what you're looking to do. What is your reasoning for joining? Education, travel, combat...etc? This will definitely steer you in a particular direction. Once you figure out your sole reasoning for wanting to join, figure out which service best fits your goals in life. Do you want to pursue an education right off or maybe you want to deploy a lot. Even though each service offers you education, some services and their AFSC/MOS' can make it a little more difficult to do if you're gone a lot. It really comes down to what type of job do you want to do and which service fits you best (personality and so on). We all can tell you how great each service is and our reasonings but you need to figure that out on your own. :). Wish you the best in your decision and thank you for even considering joining, we all appreciate you!

For a bit more background at the moment i'm in Army ROTC. This is mainly because they offered me a noncommittal slot for the semester due to my major. If I stay with them I have a very high chance of being offered a scholarship slot. I had missed the deadline for the Navy ROTC program application due to not knowing where I was going to college yet. I decided to take the Army slot because they would give me a chance to see if I liked it as well as getting me some extremely solid references if I decide to switch to Navy. My father is a Marine and my grandfather was in the Army Air Corps and then the Air Force. My father is the strongest man I know and I've lived around the Corps my entire life, those two things are what make me lean towards the Marines. The Navy is pretty much just an extension of that along with the fact that I've always loved seeing the ships and the water. The Army is the one that has the most diverse job fields and to be frank its the easiest for me to get into at the moment. I've never liked doing the easy thing just for convenience but in this case i'm trying to make sure I don't discount it just because its the easiest out of the three.

Leon, as a junior in high school, I decided that helping South Vietnam was a just cause. I did my research and decided on the Marine Corps. Because my parents were both deceased, I was living with my sister, who was against my choice. My friends all thought I was nuts, but I joined after high school with my plan being to make it a career. In Vietnam, I heard that we had landed on the Moon, and I thought that would be a good career. I ended up only serving 4 years, but spent 33 years with the Space Program. Two points to make: 1. Even when you plan things out, life sometimes takes you down a different path. 2. The decision is yours to make.

Please keep us posted on what you decide. Best wishes!