Work done in ~3 weeks. I don’t know how many man hours.
The full resolution images physical size is 4800 x 2700 in pixels and it took about 20 hours to render in Blender with my GTX 960 TI GPU.
When it was rendered, I took one work day to edit it in Photoshop. Some glow effects made up, vignette and depth of field. For depth of field effect I used a separate pass, called “mist pass” that I rendered out as a separate layer and by using it as channel, I could blur the background areas only without blurring any important elements.