Best part of this class: No lectures to attend. All "lectures" are recorded from previous years and can be watched at your own pace. The listed lecture times are more like office hours, and are completely optional.
The work is divided into textbook problems, which are trivially easy and just require patience, and projects, which range from manageable to fiendishly difficult. If you have a general understanding of computer science principles and know at least one object-oriented programming language, there isn't much to actually learn about C++. Smallberg is a straightforward lecturer, but I'd still recommend watching on 1.5x speed and skipping around.
Discussions were not worth attending at all. Both the TA and LA were completely checked out and it wasn't really clear what any of us were doing there. The best TA to ask for help during office hours is Fabrice, sadly he was not my TA for discussion. Office hours tend to be packed right before a project is due, start things early so you can go hassle the TAs early.

WOULD NEVER TAKE AGAIN

Should be opt-out—too much work. The tests are too pedantic to be testing on anything useful.

This class introduces you to the basics of programming, particularly in C++.
For a person with a background in programming, like me, this class wasn't too bad. His lectures are clear and project specifications are precise. A downside is that the workload is... a lot, to put it simply. You're always going to be working on the next project or homework, but as long as you start early (like the DAY it is assigned), you should be fine.
If you're new to programming: definitely expect to struggle in this class.While Smallberg is a good lecturer, he's can be uncooperative and unhelpful outside class to those new to programming - make sure to use your TAs, the UPE center, and another centre specifically for CS 31 and 32 students if you need help with projects, which you most likely will. The biggest advice I can give you is to take this class during winter or spring quarter (not fall, with all the CS majors) so the grading curve can potentially work to your advantage.

Smallberg is great overall, and you probably won't have much choice but to take him anyways so some advice for the class because there are a couple really specific tips:
MOST IMPORTANT on the midterms make sure to look at the point values for each question. You can't assume the multiple choice questions are just worth a couple points sometimes there can be an insanely heavy weight on one or two of them. On one of the exams there was one multiple choice that was worth 12 points out of the 65 pt test, be aware of that kind of weird distribution so you know how to budget your time
Don't underestimate the final. The midterms were much easier than the final, and the practice finals were also much easier than the final.
If you are going to email Smallberg for a question I found that he was much more responsive if you email from your ucla address instead of a personal one. Don't know if he has some kind of filter on his inbox or what but that worked for me and he is great at communicating
Also random note because the grades are kind of a black box I think he up curved our class due to low exam averages because I ended up with an A- after what I thought was an 86 ish overall percent

Smallberg's lectures were thorough and useful, if a bit dull. He is super responsive to emails, so feel free to ask him questions (but do that after asking TAs for help first).

The exams (2 midterms and final) are difficult but not exceedingly so. Most exams consist of analyzing code for mistakes or to understand how to works. The code in exams seem to be purposely written confusingly, so make sure you are careful when reading through it, and just do a ton of practice problems tracing through code.

Projects are the meat of the class. I thought Project 3 and 5 were the toughest, and I personally spent up to 20 hrs in a week working on those projects. However, all the proejcts are definitely doable, you just need to make sure that you start early.

I personally found the required textbook pretty useful. Usually I listened to lecture first, then go through the textbook to review and go through their exercises/problems to understand the concepts before working on a project.

Overall, I felt I got a good understanding of basic coding concepts in C++, and as a nonmajor I felt pretty confident throughout the whole course, even if sometimes it was a bit stressful trying to finish a project

It's Smallberg. Who else would you do CS31 with?
He blessed my quarter.

Smallberg's CS31 is extremely rigorous and time consuming, but you will learn a lot from it. Homework usually takes around 5-10 hours a week (depending on how proficient you were at programming before taking this class). The best part of his class is that he sends you recordings of lectures, so you can watch them at your own pace. He talks in a very clear way, albeit a bit mundane at times, and uses plenty of examples. If you spend enough time and effort, you will get a lot out of this class. His midterms were not too hard, but the final was hard. I don't think the class was curved because it took place in fall quarter (most CS majors take CS31 fall quarter).

Asynch Lectures, some of the projects/hw can be difficult so go to Office Hours. Midterms and Final are harder, especially final which shafted some people

Pretty manageable class, especially if you have prior experience with CS. Definitely do not procrastinate on starting your projects and you should be fine. Attend discussions if you need help but neither discussions nor in-person lectures are required.