Above post brings up some good points. Here are some of my tips for evaluating reviews.
1) Does the review cover both strengths & weaknesses of the headphones?? (all headphones even the most expensive TOTL headphones have flaws, there is no such thing as a perfect pair of headphones, only a pair of headphones that "perfectly" fit your tastes or a pair of headphones whose flaws are not important to you).
2) Does the review include relative comparisons against other current market options? The majority of audiophile terms are actually relative, so without a reference point, you can actually write whatever you want. A review needs comparative reference points for any meaningful information to be pulled out. A lot of times you will need to deduce the "reference point" that the reviewer is using for the audiophile terms if they are not explicit about this aspect. Either look at their preferred/primary gear set-up or their other reviews to get a sense where their unstated sound signature preference is. An 'audiophile' description in a vacuum is worthless as they are all relative terms. It is actually possible to describe the same sonic characteristic in either a positive or negative way depending on what you are comparing to.
3) Does the reviewer acknowledge his biases or mention his preferred set-up? All reviews and reviewers are biased!! This is a subjective hobby and people are looking for different sound signatures (and weigh different sonic qualities differently). This information is extremely important to gauge how your own personal requirements fall relative to what the reviewer is looking for.
4) Does the reviewer claim to be an expert or have golden ears? I personally feel that any sonic change worth describing should be audible by everyone (even average Joe pulled off the street) as long as the listener knows specifically what to listen for. The more of a 'guru' someone claims to be, the less seriously I take their opinion.
5) Does the reviewer have differing beliefs than you? (examples can include subjects ranging from burn-in, cables, sampling rates/bit depths, and having special hearing abilities). If you have different fundamental beliefs on how audio works, impressions may not be as relevant for you.
6) Does the reviewer misuse audiophile terms or contradict himself in the usage of specific terms? A lot of sonic characteristics are inherently related and affect other aspects of the sound. There are certain common patterns on how FR changes affect the sound, and often you can draw pretty extensive conclusions just by picking up on a few key words (if properly used). Also, note that it is possible to describe the exact same sonic characteristic in either a positive or negative way. Look for more relative comparative usage of audiophile terms rather than absolute wording.
7) Does the review talk about the relative degrees of difference? There are often a lot of sonic differences you can pick up after extensively playing with some gear. Some differences or sonic characteristics are more dramatic than others.
8) Does the reviewer talk about performance
rice & other market options? There are many decent headphones, but when placed at a specific price point, they can become either extremely attractive relative to the current market or extremely 'overpriced' for what they offer. I haven't really found many headphones that are so horrendous that I think everyone will hate them, but when you closely examine the price point offerings of all competitors relative to a specific pair of headphones, conclusions can be made about relative value.
9) Why is the review being written? The best reviews (in my opinion) are from personally purchased items written by non-professionals. Professional reviewers operate in a different setting. Their access to review gear is dependent on review samples sent by companies and they are required to establish relationships with manufacturers. Their profit margins are determined by their visibility and audio gear sponsors. What they write will be more dramatic than reality and often tilted more positively. If two things sound exactly the same, they can't just write that. Expect a lot of flaws to be glossed over in professional reviews. Expect a lot of jargon or other writing styles that project a sense of authority or expertise over the average listener to give more credence to their subjective opinions over others. They have to met deadlines, are required to write about the gear that they are assigned, and have to follow certain guidelines set by their editors. Do note their work also provides additional benefits (discounts/freebies) as well as a secondary source of income.
10) Temper your expectations. Expect that any difference that is written about to be like half as dramatic as the review makes it sound. The nature of writing about subtle differences in audio gear inherently makes things sound exaggerated. There is actually an upper limit of how "good" or "magical" things can sound (primarily determined by your source files). Both positive or negative reviews are usually more revealing of the reviewer's personal sound signature preferences rather than the actual headphones performance.
I personally try to write my own reviews in a way that is more universally relatable, but I'd be the first to admit that there are certain sonic attributes and sound signatures that are more appealing to me personally. To gain helpful information from a review (imo), you need a reference point to relate your experiences to my experiences, and you need to judge whether the things I mention are important to you or what you are looking for. People perceive relative differences between different sonic attributes differently and also have different "goals" or ideals on what things should sound like.
In conclusion, there is really no such thing as an "universal review" or 100% trustable review. However, I have personally found that I have been able to draw helpful information from all reviews. Some reviews simply require more reading in-between the lines. How accurate a review will be to your experiences depends on similar your preferences and sonic impressions on other gear are to the writer. Hope this perspective from someone who enjoys writing reviews is helpful