I'm more of a mix, stealth first until I've had enough stealthing around. Though in games like this and MGS, its typically when I don't hide bodies and guards go on alert, that I stop stealthing around, lol.
Thats a big odd, but I guess they just don't have too many bullets hiding around. I know that they game doesn't limit you or anything with stuff you find, I heard you can get rocket launchers and stuff right away if you can find out where they are hidden.