As Jack Nicholson's Joker character once so eloquently put it, "Hubba hubba hubba, who do you trust?"
As a scientifically-thinking individual, I can't believe anything I haven't tested myself. I also can't test everything myself, so I place my trust in entities or websites who seem to follow the methodology I would use if I were doing the tests. True, they could simply be paid stooges of the camera and lens companys, but I'm comfortable using them as a guideline based on pure intuition. Sometimes it's all we humans have - a hunch.