Pretty controversial opinions ahead, but hear me out:
Corbin is a really engaging lecturer--he knows his stuff so well he is able to go full speed into his lecture barely referencing his notes. He's really funny and straightforward. You really go deep into understanding mechanics in this class.
His tests are hard, but not in the way you think they are. They don't have numbers, which often freaked me out because I was always scared I algebraically did something wrong. They are also only 50 min long, which means you have to think quick. However, the actual content isn't terrible---very doable if you've mastered the homework. Yes, it isn't the plug and chug you do in other physics courses and you often leave the exam uncertain rather than confident, but when you get your test back you often did better than you thought. I think I could've gotten an A if I did homework more consistently (which he frequently warned us about), but since it wasn't collected, my laziness took over.
My one complaint was that office hours were directly after class MWF, which didn't work for a lot of us because we had 20B that time.

Corbin is the best for 1A/B/C. Why?
No BS: no textbook required, none of that "Mastering Physics" nonsense - and he makes sure to call out that BS for what it is
Engaging lectures: it's entertaining and you're gonna *want* to go, which is good, because lecture is incredibly central to the class

Other notable features of his classes, which are good for some people but not others:
Optional homework: so awesome! but with great power comes great responsibility - basically you could save a lot of time by not doing the homework, but if you don't already have the experience to be sure you do well on his tests, you're gonna need the practice
Challenging tests but generous curve: it's a learning experience in itself
Super popular office hours: obviously they must be good, like the lectures, or they wouldn't be so popular - but I basically never went just because of how packed they tend to be. The man needs a bigger office. If you want individual attention, you might want to look to other resources

You're gonna learn, you're gonna like the lectures, and you're not gonna have to put up with BS. Take his class.

Best professor in physics ever, though I'm not a physics major. Corbin is so nice and funny and accessible to students. He definitely cares about the students and the test are doable and a little hard.

Brent Corbin is a legend and is undoubtedly one of the best Physics professors out there . His test were so well written and his explanations were just amazing . I have always loved physics but the way Brent Corbin "preaches" the subject is paranormal . His Office Hours are always worth going . I used to sit in each of his office hours and I didn't regret a minute of it . Believe me folks , you are a bruin which implies you are intelligent and so don't run behind grades because what matters is how good you learn and I am hella sure that no one can make you learn Physics better then this godly person does .
JUST GO FOR IT .... YOU WILL HAVE THE BEST TIME OF YOUR LIFE

By far the worst instructor I've had at UCLA. The physics postdocs, who are primarily doing research, teach the physics 1 series far, far better than this guy. This guy's only job is to teach, so its sad that he can't even outdo the overworked and underpaid postdocs.

The so-called "handouts" that he occasionally uploads throughout the quarter are hastily written, short, and pretty useless. He may as well just not upload anything onto CCLE. He just lectures off the board and his lectures are very average. Office hours are so packed that often one cannot even see properly. His office hours are a real pain to attend.

If you look at the grade distribution of other instructors teaching this class, you'll notice that Corbin's grade distribution is harsher. In other words, despite teaching this class in a mediocre fashion and giving tests too long to finish in the allotted time, he goes on to punish people with his curve.

Avoid this instructor and retain your peace of mind. Take it with anybody else.

Corbin is the best lecturer I have had in my time here. His midterms don't test how good you are at physics, but how well and how intensively you have done the practice problems from the textbook. After taking this class, I found 1B much easier than those who hadn't taken Corbin's 1A.

For those who are wondering how Corbin grades: I got 60/90 on the first midterm (~20 points above median), 28/90 on the second midterm (~10 points below the median), and felt I did really well on the final to pull off an A-.

I was sure I was going to get a B after seeing my score on the second midterm, but Corbin assured us that he looks at individual scores on the final, and rewards improvement. The final has a lot of derivations related to gravitation, which if you study beforehand, makes the final very doable.

Overall, doing well in this class is achievable with hard work.

This class was a lot of work. Going into it I knew I would have to work incredibly hard to try to get a passing grade, but as time went on, I stopped working as hard -- BIG MISTAKE. The hardest part about this class is undoubtedly the tests, but more specifically studying for the tests. I only really started studying for the tests/ doing homework problems about 5 days before the test (sometimes like 3 days). This was definitely not the right approach. You have to force yourself to do the homework early. Although it's not the best representation of what'll be on the test (given the homework uses numbers and the test only uses variables), it will get you used to the equations that you'll have to memorize for the test, and what each equation means. I would recommend going to office hours and go with at least one question- this way the professor will get to know your name and know that you care about your grade (which I think helped my grade in this class). But if you start your studying for the test like the week before the test, you should have questions about processes and when to apply concepts, which will clear things up in finishing studying for the test. Ultimately, when studying, I would say to start early and review ALL of the examples he gave in class and make sure you can do those yourself, and, especially for electricity, go watch youtube videos to possibly go through example problems and have them explain how they work. I would say the second hardest thing in this class is understanding how to solve problems, because he doesn't like doing homework problems for you in office hours, so it makes it difficult knowing how to actually solve problems -- for this, I would go to your TA's office hours and have them solve it. Although, they might not be the most helpful, at least you'll see a process and approach to a problem you're struggling with, and then you can try to read textbook examples/homework examples to try to understand the process better.

Undoubtedly a difficult class, but I would say to not get too comfortable in just going to class and taking notes. Like, every weekend you should try to do homework problems/example problems to try to re-understand your notes, because it'll make your studying for the test a lot easier if you are more familiar with the in class material, and don't have to spend hours trying to re-remember how he approached a certain problem.

I know this was a lengthy response, but I am trying to give my advice on how to approach this class, if I were to take it again.

This class is a fever dream. Every single lecture I walk out with a bunch of notes that don't make sense to me. I rarely ever confidently box an answer on the exams. I truly believed that I would not be able to pass the class. But as long as you put in the effort to dissect his notes and do practice questions, the curve will save your grade. This is not to say that Corbin doesn't know what he's doing- it's actually very clear that he knows a lot about what he's teaching. It's just that he's not the best when it comes to breaking down the concepts he's presenting in a clear way. There are also no recordings/ zooms/ adequate resources or prof notes/ slides to refer to when studying. I felt pretty isolated in the whole process, so make sure to go to discussion and office hours at the very least.

This class will kick your ass. About every engineer I've talked to has a Corbin horror story. Get ready for tests with averages in the 30s and content that makes you question your choices in life. Electric fields and voltage distribution is the hardest content I've been exposed to in my first year. All that being said, Corbin's lectures are engaging and he is helpful during office hours. He's a bit scary and will shoot down any questions asked during lecture, so save any of that for office hours. There is no safety net if you miss lectures as everything is 100% in person on a chalk board. At the end of the day, the grade distribution is pretty fair as it is most A's and B's. I was in the 47th percentile of the class and got a B. All in all, you'll have to work for it and accept you'll be confused a lot of the time, but it's not the worst thing in the end.

He is an astounding professor. If you are looking for a proper understanding of physics, take this class. Otherwise, absolutely avoid it. There was another review that said that you should not take this class unless you have a deranged need for complicated physics problems. I have a deranged need for complicated physics problems, so I liked it, but I would not recommend it to anyone just looking to get through their physics 1b requirement.