Once in a while I get an email from someone who bought a bicycle after reading positive things about it on this blog, only to discover that I also had other, more critical posts about the very same bike. When this happens it is only natural that the reader feels some degree of betrayal, and that I in turn feel guilty. I start to think that maybe I should wait until I've owned a bike for years before reviewing it, and that I should generally try to tone down the enthusiasm in my posts. But frankly, I don't think that would help matters. Having started this blog as a beginner, my preferences are in a constant state of evolution, making me an inherently untrustworthy reviewer. And I think the bigger issue is that all bicycle reviews are to some extent unreliable for these same reasons, and that reading them at face value is a mistake. Just consider the myriad of factors that can shape a bicycle review. Do you keep them in mind when interpreting the author's feedback?
Reviewer's physical characteristics
This one gets overlooked a great deal, but I think it's an important place to start. Consider, for example, that a cyclist's size and weight are going to affect their experience of any given bike. Unless you are similar in these characteristics to the reviewer, you may not experience the same bike in the same manner: a bicycle that feels perfectly comfortable to them may feel overly stiff (or overly flexible) to you; a bicycle that is perfectly proportioned for them may feel ill-proportioned to you. Physical strength and degree of fitness plays a role as well.
Reviewer's cycling background
How experienced is the reviewer at the time the review is written (that last bit is especially crucial to pay attention to when reading old reviews from bloggers who have since gained more experience)? And what type of cycling background are they coming from? An evaluation of a bicycle as fast/responsive by a seasoned racer is going to have very different implications than the same evaluation from someone whose experience has been limited to beach cruisers. Same with the notions of comfort, stability, and so on.
Basis for comparison
What other bicycles has this person ridden and owned? If someone has never ridden a Dutch bike before and they review, say, a Batavus, their impressions are likely to be of Dutch bikes as a general concept rather of Batavus specifically, simply because the whole category is so new and striking to them. Same with racing bikes, mountain bikes, and so on.
Duration of experience
Beware of statements such as "The bicycle felt great as soon as I started riding it," or "I knew right away that I loved it." And yes, I am probably guilty of making them myself - we all are. But the truth is that our impressions of bicycles change as we experience them across different contexts, and to experience them across different contexts we need time. How often and for how long has the reviewer been riding the bicycle? How long are their individual rides compared to yours? If a bicycle causes pain or fatigue after 50 miles, the reviewer whose rides are limited to 20 miles will be unaware of it.
Does the reviewer use the bicycle for the same purpose, or in the same way, as you would use it? The author's feedback is only truly applicable to the reader when that is the case. But if a bicycle is praised for loaded touring, whereas you are planning to commute on it or use it as a roadbike, chances are you will not experience its ride quality in quite the same way as the reviewer.
Every reviewer is different in terms of what it is they value about a bike. To some it is important that they feel no road vibration, whereas others could not care less. For some toe overlap is unacceptable, whereas others won't even notice it. Some care mostly about how a bicycle handles loaded, some have distinct seat tube angle preferences, some take note of how cleanly filed the joints of the frame are, some are concerned about the quality of the paintjob. There are loads of issues like this that a reviewer may omit simply because they don't care one way or the other, at least at the time of the review.
Pattern of bias
Once you read a handful of reviews by the same author, a pattern of bias will usually emerge. Some reviewers criticise the heck out of all bicycles as a matter of course, so a "positive" review from them still looks pretty negative. Conversely, there are those who are enthusiastic about all the bikes they review, and then you have to carefully read between the lines and try to determine what they might be omitting. There are those reviewers who are prone to the "honeymoon effect" and those who keep a cool head. Reviewers' impressions can lean toward the emotional, the technical, the superficial, the overanalytical - you name it. Whatever their specific pattern may be, it holds clues for how to interpret that reviewer's feedback.
No doubt there are many more factors worth considering, and I invite you to share your own strategies for interpreting bicycle reviews. More than anything, I think it is crucial to read as many reviews of the same bike as you can find - and if a common thread emerges, that's when it becomes truly informative. Also, for those bicycles we don't get a chance to see in person, the images offered by reviewers can be more telling and detailed than those provided by the manufacturer. Reviews are usually useful, no matter how biased. But to "trust" a single reviewer because you like their blog or find their narrative style entertaining is, in my opinion, asking for trouble. There is no such thing as a reliable narrator, and bicycle reviews are no exception.