The Nikon Z 6II and Z 7II are very effective improvements on the original Z 6 and Z 7. The sensors, AF points, build and handling are largely unchanged, so you probably wouldn’t pay swap an existing Z 6 or Z 7 for these, but for anyone new to the full frame mirrorless market, these two cameras are...
Controls; handling and ergonomics; Continuous shooting performance; 4K 60p video (soon; for the Z 6II)
Relatively modest upgrade; Twin card slots use different formats; Tilting rather than vari-angle screen