CineD, the people that I trust the most for testing things like rolling shutter and dynamic range in cameras, have released their results for the Canon Cinema EOS C50. It appears to be a mixed bag as far as the results go.
Looks like it offers worst rolling shutter and less usable dynamic range than the much more affordable Nikon ZR. Canon needs to start dusting off some of those patents
That's in open gate. You can't use that video metric against a camera that isn't filming open gate. By comparison, the Lumix S5II films in open gate with a rolling shutter speed of 25.4ms. Using more of the vertical height of the sensor is detrimental for rolling shutter performance.