As with any material, the visual differences between granite and quartz are a matter of taste. Some people prefer the natural and unique look of granite. Others like the wider variety of patterns and colors offered by quartz.
Granite is often cited as the most durable natural countertop material available and is known for resisting cracks and chips. As a manmade material, quartz rates a bit higher on the hardness scale and is slightly more resistant to damage.
With proper annual re-sealing, granite is very resistant to stains. Minor scratches or dings in granite can be filled in with color-matching epoxy or resin. Quartz is a nonporous material, which allows it to repel coffee, oil, and even food coloring without sealing.