Review from a student who took Classical Mechanics
Daniel Heinzen is not the worst professor but hes not very good. On a scale of 1-10 I would give him a solid 4. He didn't tell us our midterm grades basically ever, you get the impression that he couldn't be bothered to grade them. His lectures are understandable but nothing to write home about. I actually worked under this guy for a while and he's a genius in the lab and would probably be a lot better at teaching a lab course (modern lab or senior lab). TLDR: Pretty bad, not horrible. You could do a lot worse.