I agree, I have seen many instructors teaching and have seen their students in the water, as well as debriefs. I have a fair judgement of who is really good. But, for the OP, of all the people who post on this and other threads, how does he know who provides credible information. I have seen multiple people in the past ask the same question, and they immediately got a response of, " I just took full cave from X, and they are a great instructor, and I highly recommend them", which makes me stand by what I say, getting comparisons inorder to sort out who is best is rare, since so few can compare.
That makes sense. I didn’t think of it from the new cave diver that really couldn’t know if they’re instructor’s good or not angle.