Finding the Prius w/ Black interior more difficult vs other cars to keep clean. My CT is black/ black and we have three other cars with black interior .... the shinny black accents are particularly hard to keep tidy and .. IMO don't add anything to the interior. Nor does the white. The car has too many cracks and crevasses -- and the black plastic has a shine that shows everything. Toyota needs to send some stylists over to Italy and Germany -- ugly stuff.
My white interior looks clean all the time. Only the black areas show dust. I keep a microfiber cloth in the car to occasionally give the dash a quick hit.
The black softex on the seats is fine -- you can't get leather on the Prius ... so only softex. It's the rest of the black plastic they use in the interior -- the plastic in our Lexus is much nicer. Both of our Gen 3 Prius have gray interiors -- easy.