I have seen some books with an average rating of 4 but with quite a number of 1 or 2 stars with even one commenting it to be the worst book ever read (or something along that line). While I find an average rating more credible the more it has been reviewed, I try to keep it mind that ratings are all about personal preference. It helps when a reviewer writes in details about why he or she gave it a low rating ("unbelieveable Mary Sue character", etc) instead of just writing generic comments like "it sucks" or "awesome book!". That's why instead of just relying on the average ratings, I will also read a few of the more detailed reviews from the mid-range ratings (2-4 stars) for a more balanced view!
