Although every university has it’s own opinion survey on classes and lessons, I also appreciate reading the entries of students in my class profiles on meinProf.de, a platform where students can rate different aspects of my teaching like fairness, assistance, material, comprehensibility, fun and interest. Especially the free text field is very interesting, because often the students give some good clues on what could be done better.
Here are the links to my profiles (they are both in german language).