While I think it's good to recognize the inherent prejudicial nature of boat reviews, let's not overlook their benefit. A good review includes test numbers and tells you the conditions under which they were obtained. It also gives you information on the features of the boat. Even in what is overall a positive review you can generally find glimpses of those things about the boat the reviewer would change. Sometimes it's their personal view only, such as one reviewer I know who would never have a lower helm on a boat 60' or under. But it might tell you the advantage of the optional engine, the one in their test boat. It likely will show and tell you if the ER is tight. They will tell you things that are helpful about the galley or the staterooms. I've read many reviews that indicated need for additional handrails or bars.
Read reviews with a discerning mind and not as one to tell you if the boat is decent but to help you understand how well it fits what you might be looking for. A review is an opportunity to learn more about a boat from a different person's perspective. I've even read reviews where the reviewer said, "I'm 5'11" and had an inch or two additional headroom in the stateroom or ER or hallway." Well, for me, that would tell me quickly not enough headroom for me. The reviewer might be impressed by something I find unimpressive. Great example is to say the boat at WOT gets 18 knots and cruises at 14 and with the optional engine is capable of 21 and 17. Well, to many that is nice. I read it and think, "darn, it's too slow."
Here are a couple of excerpts of the helpful nature:
The anchor is mounted to a stainless steel roller embedded into the bow. We’d like to see a cleat for securing the rode when the anchor is deployed to take the load off the windlass, which is not recommended by the manufacturer.
The engines are conspicuously absent sea rails but there are grab rails overhead, but high for shorter captains.
I find both of those observations valuable.
I will also echo what ksanders said and that is that most boats built today are well built. Now, there are builders I wouldn't consider either because of their ethics and integrity or their inability to meet their commitments or often because of their lack of financial stability. A reviewer isn't going to disclose those things, nor are the reviewers even capable of doing so. Their review is going to be within the imaginary walls around the boat. The big differences in boats today is the uses to which they can best be put. Also, the price range in which the boat fits. A review isn't designed to tell you a Sea Ray isn't a Feadship. It also won't tell you about warranty service or any dealing with the builder after the sale.
I could definitely write more insightful reviews. Only a couple of problems. Would have no advertisers so no magazine and would not have any more boats made available for me to review. Even Consumers Report reviews have bias though. I use to read their outboard reviews and they'd do all outboards between 50 and 60 hp. Then, shockingly, they liked the 60 hp better than the 50 and 55 because it was more powerful.
So look at reviews carefully, understanding the bias, but you can still learn a lot from reading them.