R wins this one. Keeping black granite looking nice on a day to day basis in a kitchen is not easy. If you just wipe it with a wet cloth, it is immediately smeary and does not look nice. If you are thinking of granite for your kitchen benchtops, go for the very nice brown granite that is much more forgiving.
I don't do this everytime after the kitchen is used, but maybe every second day or if visitors are known to be coming.
Wipe it down once with soapy water to rid it of grease and other cooking detritus, refill sink and wipe it down a second time then dry it with a clean cloth. The cloth must be unused, if not, it will just smear. It takes quite a bit of time.
R just sprays with Windex and then wipes it down. Much quicker.
After three years of my method, I now just wipe it down, spray with Windex and dry it. It is so much easier and quicker and bugger the extra cents it costs for the Windex.