That is a really broad question. The most important thing will be the fit between you and your instructor. So a school that will assign an instructor you will primarily work with is important.
I would also avoid those who want all your money up front. I would avoid those with an emphasis on cranking out people for the airlines, domestic or foreign.
Convenience of access will also be important since you will be making a lot of trips there.
If you say where you are located, some members will likely be local and can give you concrete input.