Is Escalante a good teacher?

Considering his objective, yes. His job was to teach them math and he decided to teach them through calculus. His unheard-of success makes him an extremely good teacher from a more literal point of view, but from a point of view slightly more empathetic to the students he was pretty harsh and his demands were almost unrealistic. His insults and the stress of his class sent two students crying, and I've seen people have breakdowns in math class, but for pretty petty reasons compared to the students in Stand and Deliver. It's the sort of situation where I think "He's great at teaching calculus, he's surprisingly good at keeping them going, but I wouldn't want him as a teacher". Which is funny because all the students seem to like him a lot, which I'm not sure I'd be able to do in the same position. I guess it could be said that a different teacher is best in each situation, and while I wouldn't want to be taught by him, and while I may think his demands are unreasonable compared to other teachers, for the students he taught he's perfect. Everything is situational, really.