The key here is "while you are in the service they cover it 100%." Now, things in the AF are different than the Army because, well frankly, you guys are spoiled.
I can tell you personally it's extremely difficult to go to college if you are in a combat unit in the Army. You spend 2/3rds of your time in Iraq, and the rest in the field or scraping for family time (if you have one, I'm not talking about parents). In the Army they have recently CUT the amount of college needed to get promoted. Whereas if you had a bachelors degree you were a shoe in for promotion, now you and the guy with only 50 hours are on the same boat. I thought about trying it while we were deployed, but the day I was going to sign up for classes we went into blackout (all outside communications shut down, usually lasting 24-56 hours), were back up for a day, and then back down again. It was like that the entire deployment.
Now, if I were only gone 6 months at a time and didn't live on a spec of sand for a base in the middle of Baghdad, sure, it wouldn't be a problem.
This new GI bill is a really exciting oppurtunity for me, if it passes. I'm leaving the military in 6 months and in looking at the current GI bill it will not cover my education. But in the end, I'm not totally dependant on it to get my education and I want it badly enough, I'll figure something.
McCain is not getting my vote for this reason and a myriad of other things. He may work great for the Air Force, but his future policies and Bush's current policies are brutalizing the Army.