I have not bought the lens, after I've looked at it at a retailer and briefly tested. The lens is offenblendig already very sharp, sharper than the Nikkor AF-S 50m f / 1.4G or 1.8G. Autofocus is fast and accurate. Processing is similar to the Sigma 35mm f / 1.4 Art. Why I give only 3 stars to this lens? Because it personally despite superb optical performance does not please me. It is too heavy and too large for a 50mm lens. My Nikkor AF-S 50mm f / 1.4 I can take anywhere, because it is very light and small. This 50 Sigma is against a real giant. It fills almost like my Nikkor AF-S 24-70mm f / 2.8 to my Nikon D800 / 610. I photograph sometimes weddings and various photo shoots, but also I photograph a lot of free time. For wedding the lens is unnecessary, for leisure too big and too heavy. I have not bought it.
UPDATE 07/20/2014:
As you can see, the Sigma boys are quick to help, and do not understand how you can evaluate such a lens with only 3 star. May read the comments on it yet, it is perhaps understandable why I rated the Sigma with "only" 3 stars.