Some may be good, but a number of them I have seen are cons. I told some students in New York a while back, don't waste your money. This guy is conning you. It's all rubbish he's teaching you. It's got nothing to do with what you want to do as an actor.
Basic training is good, because it's very essential to be able to speak clearly.
All the fine actors of today are clear. It's a myth to think it's got to do with some stuffed-shirt technical skill that's got nothing to do with acting or inspiration. It's got everything to do with inspiration. It's the clarity of purpose. Without those basic techinques, you can't even begin to move, and people unfortunately think they can.