People complained about the 5D Mark III sensor?
Yea, it's horrible. It's an incremental improvement over the previous 5d2 sensor. We don't get magical ability to use ISO 5 million that let's us see in the dark with hardly any noise that's easily correctable by LR4. It's hardly usable, don't find it any better than the 5d2 sensor. I mean, I can use images up to ISO 12800 for web size pretty easily. Geesh, it's horrible!
Guys, I don't recall reading any posts where the 5d3 sensor was called "horrible" or even "bad". This includes the madness of dpreview forums. What there's been a lot of is, disappointment in the lack of improvement vs 5d2, such as banding, etc This is an important distinction that seems "lost" on Canon fanboys. "lack of improvement" does not equate to "bad" or "horrible". The intensity of comments from those objectively pointing out this lack of improvement (in contrast to the D800) increased dramatically as they encountered fanboys unwilling to acknowledge these facts. Usually the fanboys would mis-characterize the "critical" comments by using hyperbole such as "So you think the sensor sucks, go away troll!" or give the impression the poster had insane expectations such as "magical ability to use ISO 5 million" or that the poster had written the sensor was "horrible". Ahem.
Another example: Lloyd Chambers said he found himself "bored" in regard to the 5d3 images and Canon fanboys went ballistic saying the "5D3 images are not boring!!". Well, that's not what Lloyd said. It was the lack of improvement that led to him having a lack of enthusiasm. Lack of enthusiasm does not equal "bad" or "horrible".
This, all in contrast to the simple truth that the 5d3 sensor is not a significant improvement over the 5d2 and after waiting 4 (f'ing) years for the update, that's disappointing or as Lloyd put it, "boring".