Corian (which is a brand of ‘solid surface’) is man-made and created by combining minerals and acrylics. Corian offers more accessories such as integrated sinks and coved backsplashes. Both come in a wide variety of colors. Corian is easier to get in specific colors than granite. Corian and granite are comparable in the cost of the original installation.
Granite offers a few more pros than corian in that fact that it is heat, stain, scratch and chemical resistant. Granite also requires less maintenenance then Corian and other solid surface materials.
Cracks and scratches are inevitable in Corian and though they can be repaired, its often expensive. Corian can also become damaged if exposed to heat.
Corian slabs are only 30″ wide, so if you have a wide island or peninsula, or an usual shape (id. boomerang), it will require more seams than granite or quartz surfacing. The seams are inconspicious but not invisible.