Countertop...

Material Comparison Chart
Material Price Scratch ResistanceStain ResistanceRequires Sealing Ease of RepairHeat ResistanceSink Types
Granite High ExcellentFairYes Good Good SR, U
Quartz High ExcellentExcellentNo Good ExcellentSR, U
Marble High PoorPoorNo Fair GoodSR, U
Soapstone High PoorExcellentOptional Excellent ExcellentSR, U
Limestone High PoorPoorYes Good PoorSR, U
Solid Surface Med. High FairFairNo Excellent FairSR, I, U
Concrete Very High FairGoodYes Fair ExcellentSR, I, U
Ceramic Tile Medium ExcellentGoodNo Good ExcellentSR, U
Stainless Steel High ExcellentExcellentNo Poor ExcellentSR
Laminate Low PoorExcellentNo Poor PoorSR
Butcher Block Medium GoodGoodYes Good GoodSR
Cultured Marble Medium PoorGoodNo Fair PoorSR, I, U
Sink types: SR=Self RimmingI=IntegralU=Undermount

Countertop "cleanability" studies prove that both granite and quartz are among the safest and cleanest counter tops materials on the market today, but one isn't superior to the other.

The study comparing granite, marble and quartz surfaces concluded:

"All surfaces easily met the general FDA criteria for sanitizing... Overall, there was no statistical difference in reduction after wash and rinse for any of the four surfaces. This indicates that the differences in surfaces as discussed in the introduction did not make a significant food safety difference in cleanability."
(Hospitality Institute of Technology and Management, 2006)