The Nikkor Z 24-70mm f/2.8 S got tested at DxO. The Conclusion is that it is “the new benchmark for 24-70mm lenses”:

Many professional photographers consider their 24-70mm f/2.8 their standard, everyday workhorse optic. The Nikkor Z 24-70mm f/2.8 S sets a new benchmark by which other 24-70mm lenses will be judged.

It may not have the record for the highest sharpness score, but it manages to maintain its excellent sharpness very well across the frame. The distortion, which isn’t excessive, is also corrected automatically in RAW files and its control over chromatic aberration is superb.

The degree of vignetting is perhaps a little disappointing, but it can be addressed in post-capture processing if necessary, and many photographers like to darken image corners to enhance their images. If you want the best all-around image quality from a 24-70mm lens, the Nikon Nikkor Z 24-70mm f/2.8 S is the lens to go for.

In this review, we have compared the Nikkor Z 24-70mm f/2.8 S to its closest rivals. Remember that the lenses are intended to be used on different camera systems and mounts, so the comparisons are not strictly applicable.

Dpreview writes:

The Sony is, overall, the best all-rounder: it does well at just about everything. Sony has been making full-frame mirrorless cameras longer than anyone, which gives it an advantage both in terms of technological development (especially autofocus) and lens selection. However, its focus on developing new and exciting features has left its user interface looking awkward and clunky by comparison. The Panasonic is a more feature-laden camera and yet is arguably easier to use and configure.

The Nikon Z6 runs the Sony very close, especially with its improved focus operation with firmware v2.0. In many respects we prefer the Nikon’s handling and UI over the Sony’s.

The choice you make is likely to engender a degree of commitment to a new lens system and, having looked at each camera in detail, we’d say thinking long-term about lenses is more important than focusing on the relatively minor differences between these three cameras.

DxOmark published the full 14-30mm review. The conclusion:

With its ultra-wide angle of view and truly compact dimensions, the Nikkor Z 14-30mm F4 S is without doubt a highly appealing solution. Couple that with a flat front and the ability to add 82mm screw-in filters, and the new Nikkor seems ideally suited to landscape and travel photography. While open -perture performance is a bit lacking, the lens performs pretty well only one stop down at all focal lengths, including at the vaunted 14mm focal length.

With the mirrorless Z cameras’ in-body stabilization, using F5.6 with a low ISO might not be that challenging, and it is of course of little or no consequence when used on a tripod. Given the choice between it and a lens with more limited coverage or a much heavier and larger lens with better open-aperture performance, the Nikkor Z 14-30mm F4 S seems to strike a happy medium. And with a price of around $1300, it shouldn’t be overlooked.

In this review, we have compared the Nikkor Z 14-30mm F4S to its closest rivals from other brands. Remember that the lenses are intended to be used on different camera systems and mounts, so the comparisons are not strictly applicable.

Conclusion:

The new wider Z-mount with its shorter register means there’s a lot more flexibility for optical engineers when designing lenses. The mount should especially benefit wide-angle lenses, and indeed, the Nikon Z 35mm f/1.8 S is the highest-scoring Nikon 35mm lens we’ve tested to date. Its key strength is sharpness, with good performance at the maximum aperture and exceptionally uniform resolution at the mid-apertures. This said, it doesn’t quite match such third-party options as the Sigma 35mm f/1.4 A and the Tamron SP 35mm f/1.8 Di, which achieve better sharpness when tested on the lower-resolution 36.3Mp Nikon D800E, compared to the Nikkor Z lens on the 45.7Mp Nikon Z 7. Overall, however, Nikon Z-system shooters who are looking for a 35mm prime can rest assured that the native Nikon Z 35mm f/1.8 S lens is an optically excellent choice.