The consensus among most of our physics majors is that P235 is the most difficult undergraduate physics course that they take. This is a surprise to most students considering that classical mechanics is the oldest branch of physics and Newtonian mechanics is the first topic studied in introductory physics courses. The origin of the difficulty is that powerful new mathematical approaches are introduced that underlie many other branches of physics and thus are of considerable importance to a well rounded physics curriculum. The calculus of variations, that is pivotal for understanding the algebraic approaches, is a significant intellectual leap, but students typically become facile in applying this method within a week of its introduction. The key to understanding the P235W material is to solve many problems.
My experience is that students are more successful and get more out of P235W when they interact extensively with the instructors as well as with one another both during workshops sessions and in the Physics Library. Such group activity encourages class bonding leading to enjoyable friendships at the same time as facilitating study and understanding of the physics.