You can choose from the following materials for interior window sills:
From the optics in the interior we like only marble and Helopal.
What are the respective advantages/disadvantages? What would you recommend?
We have dark marble with rough sanded surfaces with no recesses. It's absolutely super and insensitive. And you can't see the dust right away.
Marble is sensitive to acid. Important to know about the kitchen :)
It's really just a matter of taste and price. Marble is a little more delicate.