The c100/300/500 handle like a camcorder, have a more video orientated interface, decent audio inputs and options, sdi interface.
Although the full frame sensor offers even shallower depth of field, very shallow depth of field is attainable with the super 35mm sensors, as for APS-C.
The c300 & c500 come in versions with either EF mount if you want to use photo lenses, or PL mount, if you want to use proper cinema lenses with mechanical iris, focus endstops, retianed back focus through zooms etc.
I really cannot emphasize enough that if you are using a camera specifically for video then the c100/300/400 are the way to go.