Mark7829 wrote:
Is it sharp throughout the range? Center sharpness goes to Nikon. What about other criteria such as distortion, chromatic aberration, vignetting, coatings to increase saturation, reduce flares, ghosting, vignetting, AF, construction, weather sealing, aperture blades, etc, etc.
https://photographylife.com/nikon-200-500mm-vs-tamron-150-600mm-vs-sigma-150-600mm-c/6
The link you provided compares the Nikon to the Sigma C. Gene was referring that the Sigma S is sharper than the Nikon.
Here's an article that compares the Nikon against the Sigma Sport. The Sigma Sport is obviously the better lens.