I was in his math 174E, but couldn't find a page for that course, so I'll write here. I have had lot of math courses as a third-year math major, and Bonk is hands down the worst math professor I've ever encountered in UCLA so far. His lectures are fast-paced, and always lack explanation. His homeworks are ridiculously impractical and largely not related to his lecture contents, which means you have to self-learn loads of stuff and end up messing up the scores (yeah, the grading is harsh). He posted practice midterm and asked students to work through it, but he wouldn't give solutions in lecture or online (what's the point then mate?). The course materials are actually very easy, but he made it so much more difficult than it really has to be.

The least empathetic professor I know. Do not take.

This course was amazing! I felt constantly challenged and learned a lot. Lectures were clear, insightful, and engaging. Homework assignments were excellent, and the lecture notes are textbook-quality. Examinations were fair, and feedback was prompt and thorough. A couple very small gripes:
-In my opinion, we spent too much time on the section on h-rectangles, and cutting this would have made the rest of the course less rushed.
-A few homework problems had some busywork that I didn't find helpful for learning.
Overall, I very much enjoyed my time in this course and am excited for 245B!

One good thing about Professor Bonk is that he grades you on your strengths, not your weaknesses, so if you don't do well on the midterm, you should try to make it up on the final.

Professor Bonk is a wonderful lecturer... if you don't zone out when he begins speaking in math. As long as you write yourself little notes in the margins when he begins explaining what he wrote down you'll be able to understand the material.
His tests were hard, but fair if you were actually solving the homework and not piecing together your answers from the solution manuals. That being said our class didn't seem prepared for even the computational portion of the second midterm and he was very disappointed in us.
Also be prepared. Most people came into his class expecting 33A to be easier than the 32 classes, they were wrong. Bonk likes making you think, so proofs make up ~1/5 of his tests and a fair chunk of his homework.
Also homework is 30% of you're grade, form groups to check you're answers with EARLY so you don't have to regret you're mistakes early on.
He's definitely one of my favorite math professors though. I got my first A- in a math class from his class.