So you happen to have a list of these niche sites or a link to a site that reviews the review sites?
I am thinking about the car enthusiast sites/forums (where you can search for information how to fix minor issues), also places like cpubenchmark, tomshardware, anadtech, dpreview, shoptoolreview and so on. You have to get to know the forum and how they make money, whether it's a labor of love or main source of income, how transparent they are about sponsorship, etc.
The niche ones have mods which allow genuine dissent as well as other recommendations from competing solutions.