You don't realize how different the services are until you do something joint. You also don't realize how similar some of the services are until you're joint.
I've been to joint schools in the past, but I recently completed a joint school that lasted a little over two months. In that time, the cultures of the services really came out, and the reinforced the underlying differences.
The Sea Services had a number of similarities, that I usually hadn't noticed. Terminology was similar. A head was a head and a deck was a deck. We had division officers, department heads, etc. There's a chief's mess, and the roll the the chief is different from our ground pounding brothers.
These similarities weren't striking at first, until we all started trying to cope with the Army terms. And for anyone who hasn't done "joint", joint means Army, and they won't speak your language, so it's best to learn theirs. Even the Marines had a lot in common with their sea faring brothers.
The Army and Air Force were also very close. Doesn't take Einstein to realize that this is because they WERE the same, and there is a good chunk of the population that can remember back to when there was no Air Force, but Army Air Forces and Army Air Corps.
So once you look past those differences, between the services, you find another "division" in the class, those serving in uniform and the civilian members of the class. It is here you can see the similarities of service members in general. Each has a love of their country, an appreciation for their individual service, a love of their "gear", whether that be ships, cutters, planes, guns, tanks, etc. They each understand their "part" in the grand military scheme of things. They understand while some wear blue or another shade of blue or black or green or another shade of green, they're all on the same team, and they each bring something different to the fight.
But now for Sam's question. I can only speak for what I see the Ups and Downs of the Coast Guard. I'm going to start with the downs and end on a good note.
Downs:
Funding - While funding for the Coast Guard has gone up, especially since it was moved to the Department of Homeland Security in 2003, the manning and funding is not where it could be ideally. You will work on older ships. Marine Corps says they do more with less, but on scale, you will see the Marine Corps has greater funds than the entire DHS.
Mission - You will have more missions that your sister services can shake a stick at, but you will have a hard time giving each one equal focus.
Understanding - Most people will have no idea what you do. While this is somewhat understandable for the general population, where it will be frustrating is when your fellow service members in DoD have no idea. The ones who do know, know because they've worked with you before.
Identity - We have a bit of a continuous identity crisis. Crisis might be too strong. The Coast Guard has so many missions, each with it own flavor. The Coast Guard is a military service, at all times, read 14 USC 1. The Coast Guard is also a federal law enforcement power, read 14 USC 89. How does that get confusing? A small boat station in New Jersey engaged in LE may not see its actions as very "military". Sure the sailor at a Navy base who works on the pier may not see that a very military either, but he also doesn't see it as a primary mission. He might spend less time underway, over seas, but he does not see his time away from the seas as a primary mission. The Coast Guardsman at that small boat station doesn't have that "comfort". That's not an issue for him, in general, but the military aspect of the job is much more clear to the Coast Guardsman working with JIATF-South or the cutter in the North Arabian Gulf.
UPS:
People - Smart, quality people. When you work elsewhere you frequently want to return to your shipmates in blue. They know their jobs, they know where they fit into everything, and their appreciate their role. They understand the authority they have been granted. It's a small, tight-knit group.
Mission - We know what we're doing. While the missions we conduct daily in peace and war don't translate well into commercials, they are the big and small things, you likely never think of, but take for granted, and if they weren't happening, you would have a very bad day. Also, as I said PEACE and WAR. Up until 2001, the Coast Guard had a good chunk of the actual action. If you liked doing a job you were trained to do, instead of training 90% of the time, it was a good choice. Obviously some things have changed, but they won't always be this way.
"Gear" - Our ships are generally pretty old. Some new ones are out there, and newer ones are on their way. Our largest cutter is 420'. Driving a Coast Guard cutter is what driving ships is about. We rarely used a tug to pull in one my cutter. If we did, either the currents were crazy, of the port required us to.....but driving a ship involved a lot of "twisting" springing on lines and the fine use of CPP. There are some single-screw ships out there....now that's REALLY what ship driving is. In general you will see Coast Guardsmen refer to the kind of cutter/boat by its length instead of by its class. I was on a "Reliance class" cutter, however I refered to it as a "Two Ten". I have friends on "Three Seventy Eights", "Two Seventies" "One Seventy Fives", "Eighty Sevens", "One Tens", "One Forties" and "Two Twenty Fives". A few get their own names, like the two "Polar Rollers", Healy, Alex Haley, the "New Mac" and Acushnet.
Size - We're small. Now, I've heard Marines say they're a small service, but they dwarf us. There are 10,000 more soldiers stationed at Fort Hood alone, than Coast Guardsmen that make up the entire Coast Guard. Those 41,000 or so Active Duty Coast Guardsmen are charged with defending the 96,000 miles of inland waterways and coastline of the United States, as well as the EEZ, and anywhere the U.S. has jurisdiction. All that, for a service that is roughly the size of the New York City Police Department. That means if you don't know someone, you know someone who knows that person. That can be good or bad, but mostly, it's good. Anywhere you are along the coast, if there is a Coast Guard base near by, you know there's someone you can count on. And, while I appreciate the service of all service members, I'm drawn to my own color, blue.
Those are the Ups and Downs for the service. There are many I'm overlooking, but I like my shipmates, they're the best in the world.
In the end, when you're looking at a service academy, there are, maybe three main things you want to think about. The first and most immediate for you, the school. Is it the kind of school you want to go to, because you WILL have to go there before you really start serving out "in the fleet" or "in the real military". Once you've considered that....is it going to lead to a service you want to be a part of? You may LOVE the Air Force Academy, but if you don't want to be in the Air Force, then I would recommend NOT going there. There is, after all, a commitment once you've graduated. Lastly, and most "long term", will the the degree your looking at help you in "the real world" post-military service?