I'd personally focus more of my energy and money on good lighting, good glass and good skill. With that being said ... as many people in this thread have said, if you've got the skill you can make a Canon 5D MKIII look special. Just ask Shane Hurlbut. Most great DP's are camera agnostic. It's just a tool. It's how you use it. There are expensive hammers and cheap hammers, but a great carpenter can work with either tool successfully.
I've been trying to figure out what the camera's low frame rate capabilities are. Can you shoot at 1FPS to do time lapse in camera? I keep reading about the high frame rate abilities, but there is no mention of the low frame rate abilities. Would love to know what it's capable of doing before ordering. I've been using the FS700 for about 2 years and became very comfortable with how it shot low frame rate. Hoping the Ursa Mini 4.6K has similar features.