Hi all,
Granite is a naturally formed stone, therefore, to be used as a worktop especially in the kitchen it should be coated with a sealant every year to protect the porosity barrier.
Natural stone needs a bit more maintenance.
As for solid surface, all the whites will actually yellow over time, whether it's top end Corian or low-end brands. As for blacks, carpenters always advise not to take solid black as the scratches and marks will show up very clearly; better to take the ones with aggregates in them to 'mask' the imperfection.
For the sake of my pocket, I will be considering solid surface.