I could not recommend Professor Kok more. He really wants to see you do well and is committed to making the class the best learning experience possible. The material can be tough and the textbooks rather dense but he has a ton of resources to help you do well. The homework is a really good way to prepare for the tests. Kok is also just a really nice guy so go to his office hours, he'll explain anything as many times as you need.

You should definitely take this class with this professor. He makes a huge effort to structure his classes in the best possible format for students to learn and succeed in, and it shows. This class is among the more difficult ones in the AOS department for those who struggle with physics - homework and tests are definitely rigorous. He highly encourages collaboration on homework sets by setting up class study halls though, and these are worth a significant amount of your grade. Every lecture begins with a quiz on a short reading that introduces the next topic, so attendance and readings are also important. It is also very worthwhile to show up.

Overall, you'll do a reasonable amount of appropriately challenging work with a prof who is super approachable and just wants to see everyone succeed.