Wow. Just wow.
First, thanks everybody for stopping me before I bought a 1DX. I'm just an amateur with a passion, so big investment. And I found a deal and decided to just check problems and issues one time before I bought. I found you here and one other good discussion.
It amazes me Canon has not fixed this yet and is not talking about it. Amazes me. If I did not have a huge investment in lenses and two other bodies, I'd consider another brand. And then I understand they might not be much better.
I just feel the definition of professional quality is being overlooked here and what value the customer should expect for something this pricey. Not to mention how high they seem not to be jumping to remedy the situation.
I feel for you all and appreciate that I got stopped before I joined the group as another with an issue.
This probably not related to 1Dx but I doubt you would find IQ improvement comparing 1Dx to, say 70D.
Before losing your mind, let me explains.
I shoot landscape so I don't usually go mad high ISO. If I want long exposure, I will get my tripod etc.
If that was the case to you, then you will get little benefit from camera such 1Dx caliber.
The 1Dx, however, shines in "utter darkness" where you go hunt big foot or aliens.
So the biggest bet for me is the lens quality, sensor size from crop to full offers little benefit beside ISO 6400+