As we all know the camera has a 4K 4:2:0 mode and the same full frame 1080p crappy video mode that the 1DX has, which is kind of similar as the 5Dmk3. Not much aliasing but very soft in resolution. And it has some strange interpolation algorithm. In any case, no one will buy this camera to shoot in this mode, since the 1Dx does the same exact thing for half the price.
The 4K mode is quite sharp, it didn't show any aliasing and while only 8bits (too bad) it becomes a 444 signal once resampled to 1080p, which isn't bad right?
with the S35mm crop mode, we'll still have good resolution and no aliasing, but this mode records in the same format as the full frame mode (1080p mp4 420 all-I) which still looks pretty decent, and which only downside is being 420. But we no longer need super fast CF cards nor we are so limited in the amount of time we can shoot per card.