Spring 2018 - Okay. I'll speak from personal experience here. This is for 151B by the way. In a nutshell, Deutsch's lectures aren't the best, but the graded classwork and exams are very manageable. Lecture-wise, his handwriting was hard to read, and he would repeat what he writes without giving much context. Thus, it's super hard to digest the information, especially with the very algorithmic and computational nature expected of the material in 151B. However, if you need to take the class, what I advise is to truly take some time to sit through and understand the corresponding sections in the book deeply. His tests do not have unreasonably hard curveball questions, so you should end up thoroughly knowing how to do the easier derivations and how each method works, as well as advantages/disadvantages. I mean, I could tell that he's a nice professor too, as he offered to drop one of our midterms later in the quarter and curved pretty generously at >=85% being at least an A- (probably because the final had a median of 70, but in my opinion, it was pretty fair). All in all, unclear lectures, but manageable work and tests.
Winter 2020 - If you want someone to badly read the textbook to you, this is your man. I thought numerical analysis was pretty interesting before I took this class. It's not that he doesn't care, I think. He is just really bad at communicating information, even though he can speak English just fine. I would describe lecture as awkward and confusing. I tried to make a habit of reading the relevant textbook section before going to class, so that I would actually get something out of going. But then I had some unexpected life circumstances put me behind and I just stopped going to class. You don't really need to when the textbook is just as good, and more clear. He made attempts to clarify by posting slides and reviewing material multiple times, and it helped a little. Every week, the homework questions were unclear in what exactly they were asking for. So discussion became a lifeline, as well as emailing the TA. And the midterm was even worse. Both sections of the class stared in horror at the test for 50 minutes, trying to just understand the questions. But then the class average turned out to be like an 85? Honestly everything turned out well, so I can't be mad. Generous grading, reasonable accomodations and emailing. It just felt awful and boring to go through the whole process