I wouldn't join the military given the current engagement policies. I actually considered enlisting during the invasion of Afghanistan/Iraq but I'm glad I didn't given the way I fell apart a few years later, and also what I saw of their engagement policy a cople months after I started.
See, I understand that the idea of being a soldier is to follow orders and quite probably die for the greater good. I even understand that part of fighting a war is that you, as a soldier, will be sent to your death as part of an overall strategy. I however also believe in the idea of fighting wars responsibly. The idea of the military being to go out, kill people, break things, and keep killing people and breaking things until our country is safe again. I do not see the job of the military as being a police force, or propaganda tool to try and build or reform foreign goverments.
It's one thing to "Take that hill" or "wipe out that town" or whatever, even if you die trying to do it. It's something else entirely to go riding around on patrol in a hummer, with orders to only shoot if fired upon, and to be extra careful of civilians and such. Some dude inevitably pops out of a crowd and fires at you, and then you can't do anything about it because of the civilians covering for him and such.
I refuse to be a part of something like that, and to die for someone else's "feel good" morality. If I'm going to war, I'm going in to wipe the opposing side out, including Civilians once the military is done with, until we're sure our goals are accomplished and the threat presented is gone for the forseeable future.
I am a firm believe of "I'd rather be tried by twelve than carried by six" and that basically means that with the current ridiculous state of our military and govermental policy on "war" (which people have forgotten how to engage in, totally forgetting what we did to win World War II, and believing our own bloody hype) I'd probably wind up being court martialed or otherwise executed/sent to prison because I'd very much have done some of the same things guys like "Blackwater Security" were accused of. If I even suspect someone is a danger down there, I'm going to shoot them first. I'm not supposed to be a bloody cop. Heck, there isn't supposed to be anything ambigious about it.
Incidently this is one of the reasons why there were issues about our troops not having body armor, and how a lot of our hummers and such were not armored to begin with. The military was never intended to be involved in this kind of an engagement, where your typical soldiers would be driving around as sniper bait, or trying to patrol/control a civilians population they treat with kid gloves using light vehicles.
Such are my thoughts.
Also the military is based entirely around testing and politics, as well as need. Contrary to some things you might hear, you have less say in what job you wind up with than TV commercials might imply. The bottom line is that the military always needs a lot more General Issue grunts to follow orders and fill out the masses/ranks than it does leaders and specialists. Thus a lot of the better jobs depend on testing, and whom you know (I live near a Sub Base, and have dealt with enough people where the reality kind of hit me like a ton of bricks, it's also why I have no illusions about what I would have been doing if I joined).
You'll also notice that when the whole "War On Terror" started we were turning down a lot of officers who "volunteered" to come out of retirement to lead men in combat. Simply because people like that weren't needed for the most part. Not to mention the fact that sadly some of those people probably wouldn't have been politically correct enough for the mission. While people were making fun of some retired officers who last heard a shot fired in anger in say Da Nang, or during the Tet Offensive, all Vietnam hype aside, these are also the guys who were generally accused of War Crimes (as a group, only a few scapegoats appeared) after the fact for pretty much erasing entire VC villages and towns. In short people with exactly the kind of mentality we needed, and whom I would have been more willing to follow.