LensRentals.com has completed their comparison review of the Sigma 24mm f/1.4 DG Art series lens. They have put it against the 24mm fast prime options from Canon, Nikon and Rokinon. This Sigma certainly holds up well, especially when it comes to sharpness in the center. Although, the endorsement for this lens isn't quite as enthusiastic when compared to the Sigma 35mm f/1.4 DG Art or the Sigma 50mm f/1.4 DG Art.
The new Sigma 24mm f/1.4 Art lens does, indeed, out resolve the offerings from the major manufacturers, at least in the center of the image. At the edges, though, the advantage disappears. More importantly with any 24mm f/1.4 lens, try as you will, unless you really stop the lens way down you aren't going to get a flat field of focus. And if you are going to stop the lens way down, why invest all the extra money for a wider aperture lens.
That doesn't make these bad lenses. There are clearly some types of photography that this focal length is invaluable for, and in that case you just learn to work around the shortcomings. In many cases, though, the old rule that the best 24mm f/1.4 is a 35mm f/1.4 and a few steps backwards is often true.
Read the full comparison review | Sigma 24mm f/1.4 Art $849: Adorama | B&H Photo