As I said, I've loved using the GH4, mostly... Things I love about include it's small size, amazingly detailed picture, and incredible battery life. But things I've not enjoyed are it's poor lowlight performance (maxing out at 800 ISO or 1600 ISO if you don't mind a bit of visible grain), lack of decent log and just not quite reaching that Super 35mm look never mind Full-Frame.
Two cameras were recently announced that made me consider an upgrade. The URSA Mini by Blackmagic Design and the A7RII by Sony.
If money wasn't an issue I would have likely wen't for the URSA Mini 4.6K, it looks incredible. However, that honestly wouldn't have been the practical decision and we've yet to see any test footage or reviews.
But in the end, Sony was the smarter decision. And here's why.
For many jobs, clients clients choose to upgrade from my own camera in favour of a slow-motion option. For slow motion, my go to rental is the Sony FS7. Stunning camera! So now that I own the A7RII, which has Slog2, I can consistently match the look of the Sony FS7 easily giving me the perfect b-camera to larger scale shoots and interviews.