Ever since the 28mm f1.4D lens for the F-mount, I have wanted to own a fast 28mm lens. But this lens was too expensive at the time.
Then we had the Otus 28mm f1.4, Nikkor 28mm f1.4E AFS, and the Sigma 28mm f1.4 Art.
Currently (April 2023) prices in UK stand as follows:
Otus - £3759
Nikkor - £1899
Sigma - £628
What is interesting is that the design heritage of these lenses have remarkable similarity.
The Nikkor seems a simplification of the Otus, losing APO most likely.
The Sigma design seems based on the Nikkor, but more APO.
I got the Sigma - I cannot compare with the Otus or the Nikkor but I do believe its likely better than the Nikkor for color correction, and equals the Otus. In other words it is a steal at current reduced prices.