There's at least one person who runs around and gives bad ratings for no apparent reason in certain categories (morphs and "superhero" stuff seem to attract this) - if someone gives you a bad rating and doesn't bother to leave a comment, take it with a grain of salt.  I think ratings are handled anonymously here, I don't know if they record names for who rated any particular item, which would be unfortunate.  It doesn't really make much sense, not like cash is being handed out for highest ratings (thank god, so easy to manipulate that kind of system).

Comments are the best kind of feedback, and number of downloads is a pretty good indicator (at least for the packaging and presentation).