Then there are the professional reviews, which are all conflicted because most reviewers either get to keep the gear or the gear maker is a sponsor of the site/publication and the reviewer knows it. I say this as a person who's still involved in publishing reviews (of outdoor gear, mostly), and who most of the time gets to keep whatever some company sends me.
However rotten you think the adtech industry is, the state of product reviews online -- user generated, casual forum reviews, professional reviews, etc. -- is worse.
I have a standard rant about the current state of the web that I give all my family and friends, and it always ends with: "if you didn't pay to read it, you probably read an advertisement."