Nikon's booth at CP+ includes Z6 and Z7 cameras running firmware with Eye AF. We tried it out, side-by-side with the Sony a7R III, to see how they compare.

Both cameras do a good job of recognizing the subject's eye and sticking with it, even when she covers her face for a period of time. They're similarly fast to find the eye again, afterward. This recognition (and how quickly it re-acquires the eye) is key to the performance of eye-detect AF, as we're already pretty confident about the Z7's ability to focus when requested.

We weren't able to keep the images from the Nikon but will put it to the test as soon as we have the new firmware.