As of January 12, 2012: I’ve tweaked my rating system. See more info here. Now reviews and quick thoughts have “the bottom line” which are a better view of my thoughts. The “ratings” are now just here for my organization.
5/5– I loved it and need it for my personal library. Now you need to read it. Go buy it right now.
Simple enough. Basically anything rated 3 or above is worth your time.