I have seen a comparison of both lenses (35 Summilux pre and the new CV 35/1.4 SC) in a Japanese camera magazine yesterday. In the article, two example shots were shown, both were taken at f/1.4 with an M8 in BW, the subject was a young lady in front of trees at daylight (high contrast). Whereas the Summilux showed some softness and a smooth bokeh, the CV was much sharper but also showed higher contrast. The bokeh of the CV was simply ugly, swirly and harsh.
In a different magazine the CV 35/1.4 MC was compared to the Summilux 35 pre. In this comparison, two photos - taken at night against strong point light sources - both at f/1.4 were shown. (Don't remember the camera) Here the Summilux showed some flare but the CV (MC) handled the strong highlights very well.