Although I have not had much time to play thoroughly with the Fujifilm GFX50R yet, I was able to take a few decent snapshots this past weekend. Overall, the IQ is quite superb, color tonality is no less from what I expected (i.e., excellent overall), and the handling is becoming more and more familiar as time goes. It requires more steady hands, but it is relatively easy to get a sharp shot handheld with the camera (as long as you are being careful with the minimum shutter speed, I would personally not go slower than 1/(2-times-the-focal-lenght)).
Here is one of my first portrait taken with GFX50R with the GF63 lens under some bright light conditions and warm tones. For this shot, the face/eye detection was turned on, and it worked well (check the 100% crop below).