See the extensive review coverage of the Zeiss Otus 55mm f/1.4 APO-Distagon in Guide to Zeiss, which is based on extended usage and deep familiarity with the 55/1.4. Subscribe here.
You really, really, really want this lens more than any lens you ever lusted over.
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Availability will be very limited, so pre-ordering is essential*.
* The ultra high performance design requires that production tolerances be held to rigorous levels, and this is likely to restrict initial availability.
Not limited to DSLRs
While the 55/1.4 APO-Distagon is designed for Canon and Nikon DSLRs, it also can be used on the Leica M Typ 240 (as shown in my review), as well as current and future Sony APS-C and full-frame NEX cameras. And because it is a Distagon design, there are no ray angle issues: high resolving power is retained free of color shading issues.
For general cross-brand use, choose the ZF.2 Nikon mount version which can be used with a simple mechanical adapter (ZF.2 version has an aperture ring, the ZE Canon version does not).