just based on looking at it in the library images, i'd say the default has too much grain in the gray stone portion. the 'mortar/sand/grout' looks ok, though a touch more grain than i might have used, but ok.
on the rest of the presets, the grain is still strong, but because they arent set as 'stones', it's a decent texture... just not stone or pavement to me.
so, i'm bit curious why you have the default set as stone paving and the rest not. seems a bit odd. i'd go one way or the other.
If wishes were horses... there'd be a whole lot of horse crap to clean up!
Craig