Check the second protrait's background noise, not as good as I expected.
the second one sucks.... it´s not very sharp either. not a good example imho.
Exactly~How come they can use this as the offical sample!! And the model is not as pretty as Nikon's
Here's a Nikon D4 image example
shot at ISO 100 and it's not even close for me to those ISO 400 / 800 examples from 1D X taking into account look and feel of the images. I know it depends on personal taste, but I don't think ISO is the only thing we should pay attention to.
The ISO 1600 image is blurry and it looks like a shot with focus-error (may be front-focus due to recomposing after focus lock, for instance), however if you make it smaller it looks fine: resized sample of ISO 1600 shot
and the grainy background even at 100% crop looks almost the same as in ISO 100 shot above made on D4.