That's a good point. Everyone has different opinions on things, especially when it comes to creative instruments. This is especially true with music, like how certain speakers will sound great while playing a certain kind of music but then not perform as well when another kind of music is played. People also have a bad habit of reviewing something without really testing it out and figuring out all the extra features.
You also made a good point about watching out for things that only have positive reviews, especially if they aren't very detailed. If I'm suspicious about a review, I'll check out their profile and see other reviews if I can to see if I notice any trends.