I bought a remnant from a granite shop for 75.00. Diamond blade from Lowes was 30.00 for my skill saw. Got my son to lightly spray the blade as I cut it. (plugged into a gfi) Cuts almost as easy as plywood. The polished surface is much easier to keep clean rather than something with joints such as brick or tile. I actually covered my old brick pad with it. I am very happy with my new pad.
There was another member here who used granite for their hearth . . . looked fantastic. Only consideration is folks that do so must still make sure the R value of their hearth (if required) is still met -- those with ember protection only of course have no worries.