Better late than never they say. It has been some time since I uploaded some sensor results to the Sensor Database. Results for the A7 Mark 4 are good, not as good as the Mark 3, but that is to be expected with more Megapixels.
Results at 1 second places the camera in the top rankings, but performance drops off with longer exposures compared to some other models. Still overall very impressive.
Check out the results for yourself in the Sensor DB.