In response to Nik Barbour, Pinball FX2 on Win8 is actually visually superior to the PS3 version. I did a side by side comparison of the Mars table in High Quality Mode on my desktop and there was a noticable difference in texture quality on the Mars table (see background starfield) not to mention the boost in resolution. Transparencies are a weakness on the PS3 and so the sides of the Mars table look blocky compared to the Win8 version too.
Where I did sense a difference, and this is entirely subjective, is the physics, that seems ever so slightly dulled on the Win8 release.
Zen have also confirmed that they are in talks with Steam about getting a Win7 verison on there in the near future. They have said that it will have more advance graphical options to take better advantage of powerful PCs along with universal scoreboards and steam integration.