I have now had my Nikon Z7 body for two years. And Nikon is still at it improving this camera. Firmware 3.4 changes the Z7 with regard to auto focus on eyes dramatically. It also seems to work well on dog eyes. The camera grabs the face much earlier than before and switches to the eye much sooner. And the way it does it is much snappier than before the update. I have always liked the Z7 and have loved the detail of the photos and the colors. In addition to much improved auto focus with stills the video focus is also improved.
Before the Nikon Z7 I had a Sony A7iii. The Sony to me always seemed very fast to get focus on eyes. The Nikon would do it, but take longer. Not any more. In my experience the Nikon Z7 is a quicker system.
The Z7 now finds the subject much better than before. I mostly left the camera in single point focus until this update and have now switched to just leaving it find the subject. On Thanksgiving when I used the camera quite a bit had to switch a couple of times to single point focus, but 95% of the time the camera did it’s own finding.
Is it now the best mirrorless camera of this class compared with Sony and Canon. I don’t know, but can tell you that the new software upgrade was a huge improvement. To the point that it seemed like a new camera.