Hi jillgutwein,
I think that the Piatra Gray is better because the white veins and it's beautiful movement refernces natural materials such as marble: http://www.caesarstone.ca/en/The-Catalog/Pages/Piatra%20Gray.aspx

I think its important to also know what cabinets are being used or what the floor is like in order to guide you best

J Design Group, Miami Interior Designers - Miami Beach - Miami - Williams Island - South Beach -Pinecrest - Sunny Isles - Modern Interior Designer Firm in Miami, Florida - Ocean Front Contemporary Decorators - http://www.JDesignGroup.com

J Design Group, Thank you for your comments. The cabinets will be medium dark stained maple with flat fronts. The floor is 12" ceramic tile with tones of cream, gray and caramel brown. Attached is a floor photo.
Caesarstone, thank you for your thoughts as well. I actually would like to mimic concrete or stone verses marble. Would you still suggest Piatra Gray?

I have Raven with white shaker perimeter cabinets and London Grey with dark wood cabinets for my island. I love both counters and don't feel that the Raven looks flat or shows dirt easily. It is very simple and I think you will be happy with it if you aren't looking for your countertop to be the focal point.

Thank you @sarahpost for your comments! I'm glad to hear that!