I took prof. tang's CM145 class. It is pretty easy if you study hard for it. There were only 4 homework assignments and the grading was very hard. The grading was all up to the TAs and there is one TA that doesn't really understand english but still grades pretty hard. That didn't make much sense to me. However, with that aside, the class is pretty easy. Midterm was super easy with short answer questions, and multiple choice. Final exam is easy if you study hard for it. I ended up with an A in class and the subject was pretty interesting. He's generally pretty lenient with grading. I think if you get around average, you get a B+