Coming from the Df, handling of the Z fc is very easy and offer few surprises. There are video aspects of course, but these are easy to ignore if you don't intend to do video stuff. Z fc is lighter and somewhat smaller in size, which can be beneficial ever so often. For my hands both cameras handle with ease, as I don't have large hands.
The finder of Z fc is brighter and many might consider focusing manual lenses easier with the EVF. I'm not that enthusiastic as I find using in particular slower or wide lenses on the Z fc allows less precise focusing than the Df. To be fair, the latter has a split-image screen which is really helpful for such lenses.
The biggest difference for my use is that AF lenses can more easily be integrated with Z fc operation, whilst Df is superb with manual lenses. For me it's not either-or, but both.