It design is extremely comlex, with 15 elements in 12 groups, compared to 11 elements in 9 groups of its ZM counterpart. It has a $3,000 price tag and is made in Japan. It also incorporates aspherical elements and floating element design.
Ken Rockwell already published a review of this newly announced premium super wide with distortion chart, MTF charts already. Go take a look at the kenrockwell review.
Links: Zeiss 15mm page, Ken Rockwell review, Official announcement.