I use DSLRs almost exclusively for video so I really want the 6D to be my camera of choice but the moire really bothers me. I haven't used it personally so, unfortunately, the only way for me to analyze its performance is through videos posted online. This is not ideal as I often have no idea what camera settings were used, and there is always the possibility that the image is further affected when uploaded online.
I have used the MkII, 7D, and 60D (MkIII a little but not enough to say I am familiar with it), and I find the moire/aliasing in those cameras to be perfectly acceptable for my needs. But, based solely on what I've seen online, the 6D looks worse than those cameras. All I can find is people stating how much worse the 6D is than the MkIII, which I should expect for $1000 difference. But I still can't find anyone with an informed, personal, experience with the 6D compared to those other DSLRs that can tell me whether or not the moire is the same as, better, or worse.