[stdbrouw]

The kind of divisive item you describe is rare, at least on Amazon. What happens most commonly is that everyone loves something or everyone hates it, with some noise (e.g. 10% 1 or 2 star reviews). In this case, it makes sense to promote the item that has a 4.5 mean score and 100 reviews over one that has a 4.7 mean score and only 5 reviews. You want to account for the uncertainty when there are few ratings. If you don't, all the items at the top of your search results will be 5-star 1-review products.