RedShark News has a great review of the new Panasonic GH4 4K camera. Great article on the camera, though it is for PAL users instead of NTSC, but that is the only fault.
Also talks about an interesting program from Thomas Worth that is a Mac Command line app to convert the 4K 4:2:0 footage to 1080 4:4:4 footage using the extra picture resolution. Which sounds great, though I don’t know how it could have more color data.
This camera sounds amazing. I wish Canon would take these lessons to heart and make their lower end cameras have amazing features like this camera.