With deployments of only 4-6 months in the Air Force,w e have it the best for college. Also, at majority of our deployed locations we have Education Offices and are highly encouraged to go to school while downrange.
If you go Army, you will have a full schedule deployed and are looking at 1.5 years per deployment. Typically these guys also go to bare bases.
Also, the Air Force is the only branch with its own Community College (CCAF). You get college credits for: BMT, Tech School, Upgrade Skill Level, Certain TDY's that involve classroom learning, etc.
We never go "into the field" for training, so you schedule should be lite enough to do 1-2 classes a semester.