I have taken Jerry's class. I found that it is really helpful for me. Because I knew I have pronunciation problem and some sounds I could not even make. Therefore, I have tried so many ways to correct it, like talking a lot with Canadians, going to pronunciation classes, you name it. No conspicuous improvement. After I took Jerry's class, my Canadian friends told me that my pronunciation is much better than before. This is just my own experience. If you want to improve your pronunciation, and could not find a good way, why not go to his class in person, sit behind the classroom and find out by yourself. (there is no charge for the first class). That was what I did before.