While I'm not really interested in going to a full frame camera, I think it's pretty smart of Panasonic to use an existing mount. That gives them access to a series of lenses that already exist. I don't know much about them, though.
Personally, I'm piqued by the new micro 4:3 lens Panasonic announced, the 10-25mm f/1.7. That could be very good for video, and not horrible as a "walking around" lens.
I currently use an Olympus OM-D EM-5 MkII, and I love it, although it lacks in a few areas. I'd almost be tempted to try to find a used Panasonic GH5... but I am going to wait until Olympus makes their announcement early in 2019. I'm expecting the EM-5 MkIII, and hoping it ends up with a better sensor, PDAF, and more versatile video (4k 30 and 60FPS, 1080 up to at least 120FPS).