OP - why do you want to join the AF? Kind of what that asshole above said is shop around if you don't have a real concrete reason why the AF above the other branches.
But, I spent 6 yrs enlisted and traveled a bit while I was in. Never went to the sandbox but spent a year in S. Korea (which was my best assignment). Spent a good portion of my enlistment stateside.
If it wasn't for my time I doubt I would have the discipline to do the things I'm doing and accomplish what I have. I definitely wouldn't be posting right now (an old supervisor who could lift houses turned me onto this site and lifting in general).
All in all it was a great experience, I gained a lot of valuable life experience and got a few college credits under my belt - the GI Bill took care of the rest of my undergrad (which was my ultimate goal - funds for college).
If you want to ask any more specific questions I'm sure I can help.