And Canons beat every other brand in image quality.
Pentax, Olympus, Sony trailing behind Canon and Nikon.
Nikon scoring in handling, it seems.
Do you know how these studies are put together?
I've not read a detailed breakdown, but from what I've picked up, and experienced first hand, they only survey people who have bought high-ticket items (companies pay them to use the survey as a reference) and who actually registered ownership of the product. People only get one vote and they are people who actually bought the product. The survey is tied to your address.
I think they don't report on the bottom performers so as to not embarrass companies they may collect money from in the future.
I've not liked their surveys with cars (it may be similar with cameras) because they seem to survey people within a couple of months of buying the car. So you don't get to many bad things happening when it is that new, nor may you really know what you can and cannot get out of your camera. With cars they call that an initial quality survey. I think they do another one after three years called the dependability survey.
So no, from what I know random people cannot vote, you get only one vote, and it is legit. On the other hand, you are getting votes from the masses and they may not know squat other than if they think it looks cool. It could simply reflect that many people vote what marketing departments and/or their friends have convinced them the quality is, rather than what they themselves can objectively observe. Moreover, it doesn't compare models or brands to others.
Still, it shows some people are satisfied and jazzed with their purchase, and some are not. And the people who are happy may be stupid and clueless, and so may the people are not. Make of it what you will.
I don't know the details of how the camera surveys are run and the above is only my opinion from what I "think" I know. The reality may be different.