Just a personal opinion but I own a 5DIV and 5DSR. I acquired a 1DX III earlier this year. 20mp feels quite old fashioned. To me the 1DXIII processors and buffer are designed for a larger sensor. It could easily have been a 30mp sensor and it would have handled it. It may have been more for the video element they went for 20MP. I find it good for large objects but no good for small objects like birds. It would have been a much better all round camera at 30MP.