I shot with the 1DC recently and initially I was a little disappointed in the form factor and the menus. I was used to shooting with C300 and for this project we decided to pair the C300 with the 1DC. The main reason we chose it was option to shoot 4k internally to a flash card.... at the time of the project the c500 was available to rent,but the 4k recording device needed to work was not, so this became the best option for the price point of the project. Phillip Bloom did the world of cinematographers a great service by providing an honest hands on review to know what to prep for when using it. Specifically in regards to the menu I guess I wanted more simply because this Camera is in canons cinema line thus warranting a that expensive (C) on the camera I really wanted a more proper video menu.
After using the C300 I hate to say but user wise until you see the image the camera will just seem inadequate for run and gun, or some other styles of production. Say all that to say this it's Dslr yes with some great bells and whistles but it's a Dslr none the less. At the end of the day I just look at from a Director/DP/Producer/Editor/ perspective which is "Is this camera the best to execute the project, and,does the shoot allow time for rigs, monitors external sound devices, and expensive flash cards in place of external 4k recorder... if yes than this camera is for you and your project if not shop around.