Thanks for posting and good to see someone else testing sigmoid. Here are some crops out of your edit:
Lighter part of the image:
filmic
sigmoid
While I think the differences are sublte, filmic delivers a bit more contrast here.
Darker part of the image:
filmic
sigmoid
filmic crushes the shadows a bit, while sigmoid shows a bit more details. This leads to a clearer look in this part of the image in the filmic edit. Watching the rendering of the lamps, I think sigmoid does a better job avoiding halos.
Both images also show a slightly different colouring, visable in the shadow areas but also in the sand and coal. In my edit (#22) I remember that this was the point where I struggled the most. Is the sand more red ore more yellow ? How black is the coal really ?
Here is another try, sigmoid contrast = 2.25, skew = -0.35. It gives a bit more contrast to the excavator and a bit more definition in the sandy area (history in the jpg).
To get even closer to filmics result you could tweak sigmoid a bit more, especially the colour processing parameters. Personally I think both edits are close enough and would do any further editing with other modules such as tone equalizer, color calibration, color balance rgb etc.
Edit: typos