I haven't found a way to see how many quizzes anyone has rated. From what I can see, it isn't on anyone's profile. If I remember correctly, I couldn't track my progress when I was going for the badge - I just got the badge when I had rated 500 quizzes. I definitely can't see anything from the completed side of the badge.
I vaguely remember someone saying it was removed from people's profiles because it slowed the server down or made it crash (something along those lines), but I could be wrong.
"No, please don't eat me. I have a wife and kids, eat them" - Homer Simpson