Xie takes an already boring subject and manages to make it mind-numbingly horrible. It's not particularly hard material, but his class will have you falling asleep. Reading the book is much better than going to class.

Had Xie for 2C and 152A simultaneously. Contrary to how 2C went, Xie was more passionate about teaching 152A. Lecture slides are all online but he'll write out solutions and explanations to whatever he has on the slides, so showing up is optional. 152A exams were straightforward and fair, you can self-teach by just reading the textbook

Yuan Xie gave incredibly dull and blatantly uneducational lectures. After the very easy midterm, nobody really held that against him. But the final was orders of magnitude worse than the midterm, don't be fooled by him acting as if he's your friend. I'm probably not an engineer anymore after this gem of a professor.