This was his first class at UCLA, so he definitely wasn't the greatest lecturer, however, he was clearly very caring for his students and could be quite funny during lectures. His exams were extremely straightforward and I did well up until the final which I hardly studied for and rightfully did terrible on, which dropped my grade from a comfortable A to barely a B. Overall, I only expect Haoren to get better as a lecturer and I would definitely recommend him for this class.

Underrated in my opinion. He goes through material in an efficient and clear manner, and releases homework every lecture (just a few questions). Furthermore, his lectures (at least during fall 2022) were recorded, so you didn't have to attend lectures physically at all. His practice midterms are extremely similar to his actual midterms, so I would recommend doing them.

Overall, I have found this course to be very enjoyable and informative, and Haoren is an excellent lecturer who explains the material very clearly. I especially appreciate that he provides helpful notes that are useful for reviewing, and that he always uploads the lecture recordings on time. Based on my experience, I would highly recommend him for 31B.

However, I did find the final exam to be quite challenging, even though I thought I had prepared well and was hoping for at least an A-. Unfortunately, I ended up with a B+ instead. On the other hand, the midterms were much more straightforward and closely resembled the practice exams, so I found them to be manageable with sufficient preparation. For anyone planning to take this course in the future, I would suggest being aware that the final exam may be more difficult than the midterms, and taking extra time to prepare accordingly.

This is his first lecture ever taught, and I'm surprised by how fast he improved his style of lecturing. His exams weren't the easiest, but if you study hard you will end up with a good grade. Definitely would take another course with him.

Honestly, you are just teaching yourself everything. The professor reads and explains very poorly actually he does not explain. The exams he makes are very complicated and include things that he does not even go over, which is very frustrating. When the class does badly, he writes a message to the students about how badly we did. I took him last quarter too for 31 AL and he said "I went through this and suffered now it is your time to suffer" just to show that he does not care.

Haoren is a kind person and I think it is possible to do well in his class. I took this class my first quarter here and his first quarter at UCLA. I came in having done well in AP calculus AB (I got a 5 on the exam and did really well in the class). The content's logic level was similar to the material from calc AB(and I assume 31a). However Haoren's teaching method was very difficult to understand--I do best when I am plainly told which methods to use for which problems. In each class, Haoren simply started solving different problems while vaguely narrating each step with out explaining why. It felt like he was reading from the textbook. When students asked questions, he would give a quick response and then keep solving without checking to see if his explanation made sense. Sometimes when people asked him why he was doing something, he would say, "this is just what the textbook says". My TA, Zerrin Vural was great. During discussion, she would explain things in a way that made much more sense to me! Also each lecture was very similar to the textbook, so towards the end of the quarter, I started reading the textbook before lecture which helped a lot. The lectures are also recorded and he doesn't keep track of attendance. Haoren's office hours were also really helpful because he would show how to solve confusing problems from the homework and practice midterm--I found these more helpful than the lectures. The class was well organized and I felt that the tests were very similar to the practice tests. I think that I did so poorly, not only because of the teaching style, but also because of a mix of the TA strike, being overloaded by my other STEM classes, having the midterms returned 2 days before the final, and being new to UCLA. Still, I think I would have been able to get higher grades with less effort with a different professor. I would recommend trying to take the class with a professor who has more experience teaching/is better at explaining things. I know a lot of people are struggling in his 31AL class right now as well. If you do take this class, I recommend going to office hours and making sure that you understand everything in the practice midterm.
Also here is how it was graded:
15% Homework-graded on correctness, 2 lowest homework scores dropped
There are 2 midterms and a final
There are 2 Test Grading Schemes--they will chose whichever is higher
A: 20% each midterm, 45% final
B: Highest of the two midterms for 30%, Final 55%

A splendid young chap. He taught me how to write in shakespearean (proof by recursion)
But then strikes the mystery TA, who gave us secret potions (Series Tests)
PS. On the final day Xiong finally takes off his glasses and reveals that he has an evil twin named (REDACTED) who writes the final.

Avoid this professor, take anyone else. In lectures he repeats what the textbook says and talks really slowly. I had to watch recorded lectures in 1.75 X speed to understand. He doesn’t explain how topics connect to each other or why it works. His practice tests don’t reflect what will be on the exam. I studied for hours for each test and still didn’t do well. I asked him what I could do to study better and he told me that if I had actually redone homework problems I would have done better. When I told him that I did fully redo homework problems to study (in an email) he never responded. Before our final he laughed about how easy this test should be but the average was a 62. Don’t take this professor or you will have to spend hours outside of class teaching yourself the entire course.

Do anything you possibly can to avoid Xiong. Everything is self-study and the midterm average is a C. It is not worth the stress.

His lectures are not always super easy to understand, but he records and uploads all lectures and slides to Bruinlearn so class isn't mandatory at all. His midterms were easier than his final, but it was doable. Overall, I thought his class and grading was pretty fair. He curved overall grades at the end.