The reliability of reviews can vary greatly depending on a number of factors. Some things to consider when evaluating the reliability of a review include:
The source of the review: Is it from a reputable website or publication, or is it from an individual with no apparent expertise or credibility?
The motivation of the reviewer: Are they being paid or otherwise incentivized to write a positive review, or are they simply sharing their own honest experience?
The number of reviews: A single positive or negative review may not be representative of the broader experience, so it can be helpful to look at the overall pattern of reviews from multiple sources.
The context of the review: For example, a product may have received positive reviews from people who used it for one purpose, but negative reviews from people who used it for another.