It's always nice to receive praise, but sometimes constructive criticism can be more useful - I've had some really helpful comments from members of this site, often pointing out improvements I could have made but didn't notice myself.
Reading through the threads on the subject of ratings, I'd say that most of the complaints are about a small number of malicious ratings and comments, rather than genuine criticism, which is accepted for what it is - a sincere attempt to help somebody do better.
As far as I'm concerned, please keep the comments coming!