I'm not sure how comparably more vibrant colors in 3D are a sign of superior image quality - games aim to mimic reality and as we all know, in reality nature has no bright and vibrant colors. And for the record, how would we know that the colors produced by Radeons are closer to those intended by developer?
Image quality is not a subjective matter.
Agreed. That's one of the arguments that I've been debating for ages in IQ comparisons between different brands also including Intel IGP, Matrox, S3 and others.
The same happens with LCD vs. CRT. Some people say LCD looks way better than CRT because of the same reason.
It has nothing to do with the quality, anyway. There was an experiment where thay tried to test this. It was not about any brand, just an experiment to test how people saw their reality and how colors could affect people:
They showed two screens to many people with some image comparisons and ask which one looked better. It was the same picture on both screens all the time, but one of the pictures was altered with more vibrant colors, though they were false colors. They changed the false picture from one screen to the other between subjects to eliminate the screen as a factor. They showed many different pictures from different parts of the world: tropics, deserts, forest, cities... The grand mayority of the people chose the false picture. When asked about the reason they had a hard time telling why, "it just looked better for them". Only people who worked in jobs related to image (photographers, image designers, painters) where able to say the reason and most of them choosed the image that was not altered. Another interesting thing is that on pictures of cities more than half the people chose the right picture, claiming that the other one had false coloration, "cities don't look like that". This is really interesting because on the article itself* there was the comparison where most people chose the altered picture: it was a tundra like forest that looked almost as a tropical jungle to me in the altered picture!!
The conclusion of the experiment was that most people can be "fooled" by colours, and that the closer that they are to them, the easier it is for them to recognice them. For example since most people lived in cities they chose the right city pictures, nature photographers chose the right pictures when the theme was nature, etc.
*I read an article about the test and it's conclusions, not the test files myself.
