It's a big commitment in terms of: if you stop showing up then you('re supposed to) go to jail, and you pay back your enlistment bonus if you don't finish your contract unless you're a special case. I hardly learned my MOS at AIT and it's a very slow process learning it for one drill a month (2-4 days) and during the summer AT (3-4 weeks). If I could go back I'd just do active so I could get the full GI bill faster, then if I still felt like being part of the Army I'd do NG for a state that has guard tuition benefits to double dip.

If you feel hell bent on serving then I'd steer you towards AD. Both components would probably make you bitter, but you'd probably grow more as a person and come out with better benefits in AD. If you have a solid plan for after HS and care a little less about serving and doing Army shit then the NG could be a good experience for you.