Not the pattern I selected, but this slab shows the difference between the two finishes.
The Shiny "Polished" on the left reflects light more (and this was not an area with a lot of light.)
The Matt on the right looks more like natural marble and doesn't create unwanted reflections (from windows and fixtures) to the high degree that the Shiny "Polished" finish does. That is why I have chosen the matte finish for this design https://pbase.com/britestar/image/174971946 . The basic pattern is the same for either a matte or polished slab, but the finish makes a big difference. The more the light to be reflected, the bigger the difference. Shiny "Polished" is the standard finish. Matte is special order. The Matte is polished, but it does not have an additional layer of a shiny coating, It looks most like natural stone. Both finishes are equally durable.

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"While the polished high gloss finish provides a sleek, ice-like surface, the soft look of matte stones gives your space a warmer tone. The matte finish can also help soften dramatic designs, such as the robust veining of Cambria’s Marble Collection™, and actually highlight the natural stone design itself."

The design I selected from Cambria's top-of-the-line Marble Collection has gold veining that actually looks better in the matte finish. I normally like shiny things, but in this case, I truly prefer the matte finish. The difference is more evident in real life than it is in this photo.