Professor Song is an intelligent professor who knows his material. Unfortunately, he does have a thick accent, though you should get used to it after a while. Fortunately, he lectures straight from the textbook, so if you read up on the material before and/or after lectures, you should get a good grasp on it. He's open to answering questions in class, and definitely interacted with the class. He's also unintentionally funny at times. His exams are not terribly difficult, so long as you study up, and do practice problems from the books. He's not the best math teacher I've had, but he's better than a bunch, and I would take another class with him if the opportunity arose.