If you are doing evals for sessions at DevConnections or any conference, comments are really helpful in addition to filling out the checkboxes. If you liked our talk - what did you like about it? If you didn't like it - it is extremely useful to know why! The same goes for the other questions that are asked, such as about presentation skills. The goal is to always improve... as it benefits everyone ...  so metadata (even if it is not love) is very helpful!