Comment: Wohl is a good standard for physics professors. He is helpful in office hours, and the lectures, though heavy in the math at times, are well formed and easy to follow along. His exams are fair, and homework is very helpful to understand material. He writes his own textbook for 137A, which is nice in terms of cost, as well as his knowledge on the course material.
Comment: Summer is pretty intense when you have two problem sets per week, so it has to be your main focus. The exams are usually not so bad, but much more conceptual than the psets. Instructor hold useful office hours.