Let the fun begin, DXOMark has completed their review of the Canon EF 35mm f/1.4L II along with a bunch of numbers.
With the introduction of high-resolution bodies such as the Canon EOS 5Ds and 5DsR, with their ability to highlight lens flaws, it comes as little surprise to see Canon roll out new versions of some of the older models in their line-up. The original 35mm f/1.4 wasn’t a bad performer, but it was beginning to show its age. The new model greatly surpasses the original in several key areas. It is generally sharper, but it’s the improvement in geometry and uniformity that really impresses. Not only does it have low field curvature and astigmatism, but Canon has also dramatically lowered lateral chromatic aberration, with the overall effect of greatly improving imaging performance in the outer field (where the older model was weak).
According to the review, the Canon EF 35mm f/1.4L II doesn't quite score as well as the Sigma 35 f/1.4 Art in sharpness. However it seems to perform well in all the other categories against the Sigma and Zeiss 35 f/1.4 Distagon.
Comparison below (Click for larger):