Gao is pretty good. MATLAB in itself is just very interesting. There is no midterm, just weekly projects. The projects imo are very good practices. He is also very happy to help with any questions you might have. Overall, he cares about his students and tries to present the material as clearly as possible.

Dr. Gao is a very good lecturer, who definitely knows his stuff about MATLAB. The lectures are actually highly engaging, but due to the format of the class, there's little need to actually go to them if you have any coding background (which is quite a shame, because he's a REALLY good lecturer).
Dr. Gao gives the standard powerpoint lectures alongside the standard "code as you teach" thing many CS professors do, so most students don't go to lecture. I mainly went to the lab sections instead.
The class is graded purely on homework, so you only need to be able to code well. I personally found the homeworks to be much easier than CS 31 homework, for example. In fact, for all but one homework and the final project, you're even given the algorithm to code about one week BEFORE the homework is due. The only issue with the homework is that the directions are unclear. Also, there are numerous extra credit opportunities for this class, in case you lose points.
There's a reason why the vast majority of students get A's in Gao's class; the grading scheme really favors students getting A's. So take this guy's class if you have to/have the option to take MATLAB with him.

The class consisted of about 8 assignments spread out over the quarter, and one final project. The class was fairly straightforward, but without previous computer programming experience, I can see how this class can seem overwhelming. That being said, be sure to make the most of both the instructor and TA office hours, they are very willing to help, even proofread your code.

The class is very time consuming when it comes to the projects (especially the final project). However, as a person who is not very good at coding, I would suggest you pick this class any day over CS31. I took both and found M20 to be slower paced, and not having tricky midterms or finals definitely makes it preferable. This class will require some work if you don't have a great understanding with coding, but the TAs lab sections are super helpful, make sure to attend those. Also, don't save your project for last minute as office hours are before the due date.

This class was definitely not a hard one. Some things to know, the TAs are super helpful so make sure to go to their office house. Theres 8 quizzes (5 questions multiple choice). The quizzes are not hard they are usually from the lecture and can usually be checked on Matlab. There are some tricky questions though so be careful. The grading on the hw was pretty lenient since the TAs grade them. Pretty much as long as you get the right answer you will get full points (unless you get an annoying TA who always finds reasons to dock points. The final project on the other hand is graded by the professor so it is definitely not as lenient. I made the mistake of not doing the extra credit and I was literally .5% away from an A. Make sure you do the extra credit and don't rely on lenient grading on the final project because even if you get 100% on all of the projects, don't expect the same on the final project. Great class though, you should take it over the summer.

Take Gao! He is a very engaging and straightforward professor. However be warned--this class is very work heavy. We had lecture exercises, homework, and lab due pretty much every week along with the final project. The homework definitely took a long time because you had to do a lot of drawing and googling--not hard but just very tedious and took many hours. The labs were very helpful but also pretty time-consuming. The finals project took the most time by far--our report ended up being almost 100 pages. But overall, I learned a lot about Solidworks and the basics of engineering design. Gao explained things very well and taught a lot of concepts. As long as you do your work, you should get a good grade.

If you have any coding experience, M20 will be a breeze for you. I only watched the lecture videos so I could learn the syntax and see what differences there were between MATLAB and other programming languages. Professor Gao has some of the clearest explanations out there. He explains everything - and I mean everything - step by step, so you won't have trouble understanding the content. He's also very helpful on the Piazza forum. The projects were relatively easy. However, the reports honestly felt like a huge waste of time. On some projects, I spent more time writing the report than doing the project itself, so be warned. Overall though, if you want to take an easy class, take M20 with Gao!

Lectures: completed recorded and asynchronous; fairly straightforward, does some good examples, although he talks a bit repetitive at times

Discussions: a bit repetitive, but basically guides you into the weekly homework

Labs: TA helps with writing a pseudo-code for the homework, which is really nice

Quizzes: one a week; pretty straightforward questions, basically directly derived from lectures; some weird wordings but generally okay

Overall: I knew a little bit of Python coding going in and it really helped. If you know a bit of coding going in, then this will be fairly easy. If not, then the TA labs will be a really good resource.

Class felt super disorganized, I often had very little idea on exactly what the expectations were for each assignment. I also generally just felt a lack of clear communication between the professor and TA. The grading is relatively lenient, though, so that makes up for not knowing what is even expected. I would also come into this class with a group prepared for the final project, because if you don't have one they don't even prompt you to start communicating with your group, and there isn't any class time dedicated to that, you just have to figure it out.

This class reminded me of high school math classes. The material and workload aren't too bad, but it's really important that you're consistent with all the computations you're making and don't make mistakes. His lectures can be dry and based off the textbook, but I personally found going to lecture worth it. Definitely the most straightforward math class I've taken at UCLA.