The problem with many sites is - they test lens sharpness only, and nothing else. Many years and many lenses later, I learned to ignore sharpness tests - once you get a modern high quality lens (on FF), sharpness is good enough and the other qualities of the lens like bokeh, AF accuracy, local contrast (higher MTF values) flare, etc., are far more important.
PZ, for example would criticize fast wide primes at f/1.4 for corner performance, comparing them, implicitly, to slower or longer primes. Really, Klauss? Their bokeh test is as joke. DXO is fixated on "acutance" only and they do not even document what that means. They recently reviewed the 135L and roughly speaking, concluded that it was good enough for an old lens, once you get a good deal on it but the Sigma 85 is better. This is a bad joke by people who do not shoot outside their labs. The TDP guy is much more down to earth. Dpreview, IMO, publishes infomercials only, nothing trustworthy there.
Sometimes I think that KR's "reviews" are more useful than PZ, etc.
As we all see, we really need to read all the reviews of important websites like these to have a more objective and definitive information about a product - mostly lenses, before buying it.
And of course taking the most objective and reliable part of all of them:
Dpreview: to get technical information of a product (mostly bodies).
The-Digital-Picture: the comparison tool.
Digitalrev: to laugh a bit.
Lensrentals: Their primarily purpose is commercial, they do more a kind of presentation than a real review.
anyway they are more objective then the above three.
Photozone: They really have they ''bar put too high'', i do think they are the most objective out there.