Dark because it complements Bridge, Photoshop, Lightroom, Blender, Davinci and even YouTube dark themes. Even my website is dark themed because graphics tend to stand out on a dark background.
I'm messing around with Win10 again and their Dark theme is hideous. GUI Design wise nothing can compete with MacOS although I tried Linux Ubuntu for a brief moment and it looked a lot better then Windows but too colorful compared to MacOS. I only like colors in my art, GUI should stay neutral so nothing distracts from your work.
This is one of the main reasons I hate to go back to Windows but I have no other option since 3D (blender CUDA/Optix in particular) and Mac is no go and I don't think this will change anytime soon, if ever.