"Thank you for the review.
While comparing all 3 lenses at F5.6 for sharpness is valid as part of a whole review I do feel that you have overlooked the main feature of the lens that is also the main contributor to the cost of the lens. Namely, its brightness.
Getting a 12mm lens to F1.4 and keeping sharpness at that aperture is not cheap. Also keeping the size in check and using 9 aperture blades and weather sealing also add to the cost.
Will you be following up with reviews showing the Bokeh performance?"
That timely feed back reminded me that I should look into one of the main attraction this lens can offer... NICE, CREAMY BOKEH!
For those that don't know what BOKEH is...
The visual quality of the out-of-focus areas of a photographic image, especially as rendered by a particular lens.
A "nice" bokeh will help to isolate your subject from a distracting background. In general but not always, a large aperture lens will exhibit nice bokeh.