I'm thinking of getting a 1D X Mark II, just because of Dual Pixel AF and slow-mo. Anybody want to swap for my 1D C? Interested to see what existing owners think. How is rolling shutter in 4K? How is the full frame 1080p quality with sharpness dialled all the way down? Audio-pre-amp quality for ext. mic? Battery run times in 4K? The 4K crop doesn't seem as harsh compared to the 1D C as I expected (from full frame).