I don't think there is anyone who has used all cameras before, so..to compare which gives the best quality and come to a conclusion is not possible. What people might do is just to say what they are using is the best.
Same as asking people Radeon or Nvidia better?
Never ending story i guess.
I have a personal belief that all cameras belonging to a particular price bracket perform more or less the same (at least the comsumer & pro-sumer models). There will be differences no doubt, but how crucial are they really? This is especially the case when we (or I) hardly ever print anything greater than A4 size.
People can compare test-shots and resolution charts all day long. Matters not to me. As an example, before I bought my camera I was deciding between the Nikon 5700, Sony F717 and the Minolta 7Hi. Sure, the Minolta supposedly had poorer image quality, but it's really too subtle for me to be bothered about it.
FWIW, the best image quality ought to belong to pics produced by medium-format cams with digital backs, no?