Leaving a negative review on a website is harder than you think. Especially on manufacturers’ web sites. The reviews are often moderated and any negative feedback is quickly policed. Even one-star reviews politely written are quickly removed or responded to in a way designed to remove the impact.
One time I tried leaving a negative review for a big ticket item on a popular UK home DIY website. It was an honest review about the quality of the item and lack of customer support when I complained. I quickly received a response saying my review failed to meet their feedback policy and would not be posted. They did not tell me why it failed or how I could correct it. I changed the text but left the one star and it failed every time. All other reviews were at least four stars. So I left the original text and gave it four stars. It was accepted.
I conducted some research and found that others had also figured this out and were using it as a way of leaving negative feedback. They would give the item they were reviewing four or five stars but the text would be negative pointing out all the flaws with the item. It appears that this technique is bypassing a weak filter, possibly human, designed to flag any review of three stars or less for a more hands-on review, or in some cases an outright rejection.
It does call into question how useful such review sites are if they can be gamed in such a way. I’ve learned not to trust reviews on the actual product or service’ website and to use an independent review site, and maybe even more than one.