With the wild patterns of the granite the small glass mosaics seem to have fallen out of favor. The mood seems to be shifting to larger tiles and contiguous surfaces.

Buy what makes you smile.

It really does depend on the granite pattern, and how you use the mosaic. If you really love it, but it looks too bust next to the granite, add a strip of mosaic between other, plainer tile, so the mosaic doesn't compete directly with the granite. Or use the mosaic all the way, if you love it and how it looks with the granite. Your home, your choice, no fear!