I'm on iPhone so what are your thoughts
My thoughts (from using both on A7, may be slightly different story with Noctilux on a Leica):
-Size and weight are comparable
-Mitakon has better center sharpness both wide open and stopped down.
-Leica has better edge sharpness wide open.
-Mitakon has overall smoother bokeh, and more even across the frame. With near bokeh, Leica has less blur on the foreground on the sides of the frame (due to field curvature).
-Field curvature is very different for the two lenses - see the f/4 shots with the same mid-distance focus target - Leica much more in focus in the foreground on the edges, Mitakon much more in focus in the background on the edges.
-Longitudinal CA is a wash. Both have a fair amount.
-Leica meters 1/3 stop faster but has more light falloff, so less than 1/3 stop faster when you include the edges.
Overall I prefer the Mitakon rendering. Would prefer clicks for apertures and Leica build.