Okay, this is not as easy as I first thought. If you don't like travelling, for instance, it'd probably be a bad idea to do this, and if you'd have to go to high-risk areas all the time, too. And you're an American, which probably increases the risk somewhat.
It's not a good idea to do this kind of thing only for the money, either. But if you want to see these places, and it doesn't involve travelling through dangerous areas all the time (some risks you may have to take), then it'd certainly deserve some consideration. Of course you'd want to make sure that you'd be able to go home on leave every year, that you'd be able to travel in the area (to see the things you want to see), etc.
I have a friend who is in Sudan right now, for similar reasons. He's certainly enjoying it, although it is dangerous, but if you don't think you'll find the places you're going to interesting, you shouldn't do it. If you're going be somewhere for six years you need to want to go to that particular place or else it'll be unbearable.
If you do want to, however, I say go for it! Does it seem tempting, are you curious, does it make you feel excited? Will you regret it if you don't go? In that case, go. But if not, think it over carefully. And if it's only the money that is tempting, it's probably a bad idea to do it.
I hope it's not too agonising -- good luck!