The only bad thing about his lecture is he spends too much time at the easy stuff (before midterm 1) and goes super fast afterward for the difficult topics. His class is pretty clear and involves much proof rather than calculation, but the homework is extremely challenging. You should expect to see the homework requires as hard proof as he teaches on lectures. Fortunately, only calculation parts of homework are graded and the exams consist mainly of calculations.

EDIT: After the final, I changed Overall score from 4 to 2. The final exam is not difficult in terms of analyzing and prooving, but it involved INSANE numbers in 3 of 8 questions, each requiring 4-digit multiplying 4-digit for about 30 times. I actually finished the equations 80 minutes ahead of time, but still couldn't finish the calculations by the end of exam. Apparently, he did not do a single step to solve the questions after making the exam paper, or he would have discovered how absurd are the numbers he gave.

A lot of people don't like this professor but I'm not sure why. I think he teaches the material fairly decently. His lectures aren't super engaging but it's only an hour long class so whatever. The midterms involve a couple computation questions and a couple proofs. The first one was really easy but the second was a little more difficult. The class doesn't really get super difficult until the second half of the quarter. The final is pretty much like the midterms except longer. Overall I think the difficulty of the class is reasonable and I was able to do well just by paying attention in lecture, doing homework (which isn't super long or hard), and doing a couple practice problems before a test.

Basically just wrote proofs on the board for an hour straight every class. Like the other posters said, he went pretty slowly through the early, easier material (midterm 1), and the material in the second half of the quarter felt rushed. Midterm 2 was a fair bit more difficult than midterm 1, mostly because it's harder and more theoretical concepts. There are mandatory quizzes in discussion sections each week. He had kind of a weird grading system where your better MT was worth 28% of your grade and your worse was worth 12%, which I really liked. The final was fair but the numbers that we had to manually calculate on the problems were completely ridiculous (I'm talking finding the least common denominator for fractions like 1/213 and 1/327, wild radicals, and other stuff you could do as a middle schooler but just takes forever and sucks). He made his grading scale like this:
70-75: B
76-79: B+
80-85: A-

So grade-wise it's not too bad. Overall solid professor but probably not the easiest for 33A.