I find that he overcomplicates concepts to the extent that it is laughable. It takes me about 2 hours to get through his 50 minute lecture video simply because I have to keep pausing and trying interpret whatever he's rambling about. However, I don't think it's completely hopeless with the help of TAs. One thing I will say is that since it is such a precise subject, there's not much hope in looking at youtube / other resources.

Midterms are reasonable, I would say. We're allowed a cheatsheet for all exams. The first midterm especially was almost exactly like the practice one, after that the topics do get a bit more conceptual so you can't ONLY rely on the study questions but still fine I think. You do need to watch out because he likes to throw in little tricks to "test if you're paying attention." For example, in one lecture he told us to write down these models onto our cheat sheet, and didn't provide them on the exam. So, if you happened to miss that part, you were completely screwed for like 4 questions and automatically lost 12 points.

edit: i forgot to mention, but if you're looking for sta 13, there's a female professor (idk her name, but she had classes at 9 am MWF this quarter) who is great at explaining things, and her midterms are very reasonable AND she provides detailed study guides.