It took me FOREVER to find a rating plugin that worked. I wanted something user-friendly that tracked voters by username and supported custom posts (to integrate with Types and Views plugin). I was surprised that it was so hard to find- must have downloaded all of the available rating plugins before I found this!
I wish that voters/raters had the option to change their votes or view their votes, but it's not a big deal. At least the admin can delete records, so in a pinch that would do.
If this also had the ability to have a Bayesian system of scoring, that would be awesome. (The plain old "post ratings" plugin uses the Bayesian system but the plugin itself isn't as good.)