Double post!

I think it looks great. Carrera is a beautiful, classic look. It looks very nice with your Ceaserstone, or whatever the counter material is. No cleaning issues if it's on a vertical surface. On a horizontal surface, Carrera can scratch or stain, but that sort of wear makes it look better. I've seen beautifully worn slabs of Carrera in 300-year-old kitchens in Italy. It's gives the rooms a sense of history.

I would go with a "soft" white grout. Be sure to keep a damp towel handy when cooking, wipe off the backsplash as soon as possible. I agree with keenplanner, aged Carrera is beautiful.