I find reviews from bloggers, hobbyists AND professional most helpful when they provide a “review policy”. Many of the fly fishing blogs I follow specifically state that they do not do negative reviews. So whatever the review, they are reviewing it b/c they like and endorse the product, equipment, book or whatever it is.
For merchant reviews it’s tough, if there are a lot of reviews, and they are overwhelmingly in favor of the product, then I have a tendency to look at the handful of negative reviews. It seems to me that for outdoors/sporting goods products, those people that really put a piece of equipment through it’s paces tend to post more moderately or low rated reviews, even if their text suggests that they actually like the product. These reviews are much more insightful pro’s vs. con’s and tend to look at the relationship of cost of a product to it’s durability, longevity and overall longterm value.