I know that the general education program is required for one of the grants. However, does having a prisoner complete the general education program give any advantage other then counting towards reform? It is a very hard class to complete, and it is fairly easy to get prisoners to complete the spiritual classes for the reform bonus, instead.
Aside from the grant and reform score, no. While the general education is presumably helpful in the outside world, it offers no advantages over the foundation program when you're in prison.
It's worth noting, however, that the Religious reform program is only available to prisoners with a spiritual need. Many prisoners have no interest in religion and cannot attend it. If a prisoner is not an alcoholic, a drug addict, violent, or religious, there are only a finite number of programs they can attend.
The general education program is also much cheaper to run than the carpentry apprenticeship as it requires only a classroom rather than a workshop with carpentry equipment.