It's very frustrating because so many people fall for the reviewers as "experts". I remember when the first of them, a blogger, called me to interview us. "I'm writing an article about you guys and btw you should setup affiliate links because more bloggers will write about you".. we setup links naively and had no idea what was about to happen. The blogger then wrote about a competitor, and then another, rebranded as an "expert mattress review site" and before we knew it we aided in launching a digital version of a mattress salesman who is paid commission. Later several other expert site clones popped up. They are SEOd to the max and I don't see them going away for awhile. We shut down our affiliate links realizing it made zero sense and was a mistake/incongruent with our values and mission. We were downgraded in the reviews the next week.
What I found really interesting was that some of the new look-alike brands that paid big kick backs leveraged the reviewers to speed track their growth without needing to rely on adwords/organic word of mouth.
I've yet to see any of the affiliates actually use real science/data or ASTM testing methods. It's "opinion based." We just ignore them knowing we'll lose some % of traffic and just stay focused on the customer.