The reviews from the past could not be any more wrong at this point in time. If you want the worst math professor at UCLA, take Thiele's class. His lectures are horrible. You will have no clue what he is trying to prove in his lectures. He could at least title what he is trying to do, but no. No study sessions to help any of the students. It's true that his midterms are impossible, and it's true that the kinds of problems on them are things we have never seen before. You will have 50 minutes to power through 6 critical thinking problems that you will not know how to do. Studying the book's problems won't help because Thiele's problems are completely different. Best to know just the concepts. Thiele is not fair and not helpful; avoid him.
Whatever the posters said down there about Thiele's class has definitely changed in thr last few years. His tests aren't fair at ALL... I did every problem in thr book and I still wasn't prepared... I saw some types of problems on the midterm that I'd never seen in my life. His examples in class definitely weren't of that level, and neither was the hw. Don't even think about finishing the test, because imo its impossible.