The-Digital-Picture has completed their review of the brand new Zeiss Otus 28mm f/1.4 ZE lens. This is the widest lens currently available in the Otus line which also has 55mm f/1.4 and 85mm f/1.4 offerings.
These Otus lenses have very limited users due to the cost and the fact that they're manual focus only. However, for the photographers that don't care about those two things, these lenses are amazing optically.
From TDP:
Most apparent in the corner is the vignetting and its clearing causing increased brightness and contrast at narrower apertures. While many wide angle lenses render corners very noticeably blurred at their widest apertures, the Otus 28 holds things together well even into deep corners. I'm not ready to say that this lens is sharper than its longer siblings, but it performs at the top of its class. Read the full review
Zeiss Otus 28mm f/1.4 ZE Lens at B&H Photo