Joseph, I'm nearly finished with an online master's degree (mathematics) offered by a Tier 1, bricks-and-mortar university. For a self-motivated student of high intelligence, online is OK - BUT! - I really miss the back-and-forth discussion of a classroom.
I also teach high school math at a suburban Texas school. Only about 10 of my 180 students would thrive in such an environment, and half would fail. Students who are having difficulty mastering a concept need to have their individual mistakes examined and discuss their misconceptions with the instructor.