I agree with the concerns about professor rating. Students are in a weird position where they are a “customer” in a sense but their incentives are not aligned with the university for grading. They may ensure up paying $20k to have a professor give them a (justified) failing grade.

For employees, it’s a bit better. It is reasonable to look for a good work environment, and employers won’t always be upfront in an interview setting. Having the inside scoop helps the potential employee.