As Peter has said, the VC 35mm f1.2, has one of the nicest balances of modern and classic and that is one of it's special qualities. As I mentioned previously, depending if the light is of high or moderately-low contrast, the look at f1.2 & f1.4, can often take on quite different characteristics...almost appearing to be two quite different lenses.
The one area which would strengthen it's performance, in my opinion, especially against the Leica 35mm Lux asph ver. I, is where the lens places the subject within the depth of field at the wider apertures. Whereas the Leica tends to place the subject at the rear of the depth of the depth of field, so that the OOF area starts right behind the subject and therefore gives rise to a lovely soft bokeh, the VC 35 f1.2, generally places the subject more towards the middle or front of the depth of field. Therefore the area just behind the subject is also within the depth of field and the OOF area doesn't become quite as diffused or suddenly drop off like the Leica. I've noticed this is a tendency of many fast VC lenses like their 50mm f1.1 and if VC changed this aspect, I think some of their lenses would benefit greatly. Still the bokeh of the VC 35mm f1.2 is one of the nicest within VC stable of lenses.
Dave (D&A)