As a long term Canon user - and after dealing with my 5d MKII for long years - I'd say: Sony A6000 for $699.
I know NO camera makes the photographer - or videographer. BUT the camera can help you a lot to express yourself through the lens.
The A6000 is VERY small… tiny but very well made. Solid, if you wish… I've got FD and EF adapters, so I can use all my "L" series lenses and VERY cheap old Canon FDs from used stores and eBay. The lovely 135 F2.8 I've got in London for £57… and it's and amazing piece of glass. I have a "cheapoboost" for EF too…. and it's quite nice… and of course it gives me MORE light than in my MKII.
Saying all that, my video now is all A6000 and zero MKII… because I have zebras, focus peak… and in a very small body, and with nice 60FPS - or 24, and I don't need Zacutto ;)
I can suggest the Sony A6000 from my personal experience. I've been using 5D MKII since 2008, and I like the image quality… as a stills camera, for the fashion/portrait I used to do it's still a proper choice.
Las august, going to London, I just wanted a small camera with good video performance…. and my first choice was the BMPCC UNITL I watched Philip Bloom's review. My choice? The Sony, of course. THe result? I'm using JUST the A6000 with all my lenses and absolutely pleased with the results of this ridiculously small camera. Nice 24p, nice 60p, zebra, peak… and with its 50mm 1.8 even a decent "point-and-shoot-video-autofocus". With the adapters I've bee using all my Canon glasses: 24-70 f2.8, 70-200 f4, 135 f2 and even a very cheap FD 135 2.8 that looks SO vintage on the camera and gives me a fantastic bokeh for 50ish pounds!