Bob Jones is too legit to quit. Hands down the best physics professor I've ever had. His classes are always tough (I also took 1620 with him), but he's a clear, dynamic, informative lecturer and a great professor. He uses iClickers in class, which are half participation and half accuracy; I definitely find these helpful for understanding the material. The clickers are often based on the readings, which are assigned every class, approximately 2 or 3 sections from the book. He does a lot of demos in lecture, which are fun and interesting. Homeworks are long and difficult, but relevant to the material and good preparation for the exams, which are hard but fair. I didn't go to office hours that much this semester, but normally you can ask a question and he guides you through it while you write it on the chalkboard. He can be a bit intimidating, and occasionally condescending if you ask a non-instructive question. Overall, though, Professor Jones cares about his students and does his best to help them do well.