I recently had a horror story with Papa John's over a pizza order and refused to pay the check. It was supposed to be taken care of but instead they sent it to collections as a bad check.
Long story short...it only reported on my EQ report and it dropped me from a 562 to a 523. I called corporate and threatened them and their "better ingredients" and it was corrected immediately. My score went right back up to a 562.
I also have access to a lot of free pizza now, too.
I heard the same thing about collections being deleted that it wouldn't cause much of a score increase but twice I have seen nice jumps in my case.