We are currently discussing which color is best for exterior window sills. Our windows are quartz gray (RAL 7039). The shutters/blinds are aluminum gray (RAL 9007). I would try, if possible, to match the color of the window (right in the photo) so that there are not too many different colors. And my wife thinks the "black" window sill is prettier.
What do you think? Are there any other arguments besides like-dislike?
Both look good, but I would choose the lighter one.