It is not only possible, but likely, that two individuals exposed to the same system will have differing opinions about its qualities, or lack thereof. This due to both individual bias and differences in auditory acuity. Consider two listeners, one capable of hearing out to 15kHz, the other with an upper limit of 10kHz. If both listen to a system with characteristic brightness above 13kHZ, it is obvious that one listener will be more sensitive to that condition than the other. To some folks, a slightly rich bottom or subtly elevated high frequency response sound natural and neutral.
Reviewers are only human, they can make mistakes.
But for the most part I honestly feel these guys report what they hear. However, their tastes in music reproduction may not necessarily agree with yours. Therefore you must be very careful before buying a product based solely upon the recommendation of one reviewer. However, if you have read many of his reviews, feel that you are familiar with his biases and find his tastes seem to follow yours in other instances, you can be somewhat more assured of making the right choice. Read as many reviews as possible to see if you perceive a consensus of opinion.