I'm a bigger fan of Robert Cicala's (on LensRental.com's blog) cross-platform comparisons of lenses from different companies where he'll take the sensor completely out of the equation. Rental guy dealing with all sorts of equipment seems to have less bias than a testing company whose services are only hired by Sony or Nikon and not Canon.
But DXO has tests specific for the sensor. Their ratings of the different cameras might be biased, but their detailed tests are just pure data.
I also like Roger's ( not Robert ) tests, but I take in multiple sites before making any conclusions for myself. I also quite often rent before buying either a new camera or a new lens. Nothing like testing things out for yourself using the equipment under the conditions you shoot.