I've shot video with both, and the moire is about the same. It just "feels" like there's a slight bit more on the 6D but even then I ask normal people if they notice or care about it and they really just don't. So I wouldn't throw a temper tantrum over moire just yet, if you want pro results then you gotta pay pro money. There are more advantages on the 6D for video over the 5D mark II, very important advantages at that. Most noticeable practical differences are the amount of video modes, and the visible audio meter while recording. Overall audio features (like the headphone jack) not as great as the 5D mark III, but definitely better than the 5D mark II. That's why we always use the 5D mark III as a main camera, and close ups for lapel mic'd shots. And of course, the primary yet somehow not as practical reason of getting the 6D over the 5D mark II.... Better noise performance at high ISO. It performs quite well in that department. (Just remember that quality of light will always determine better IQ over high ISO performance.) All in all, yes, 6D is better for video.