It looks like Metal Gear Solid: Ground Zeroes will have exclusive content on PlayStation platforms. A photograph tweeted by series director Hideo Kojima today from the PlayStation 4 launch event in New York makes mention of this fact.
Take a look at the photo below, and look above the “Spring 2014” text on the banner to the left. You should be able to make out the line “Exclusive content for PlayStation platform”.
Metal Gear Solid: Ground Zeroes is in development for Xbox 360, Xbox One, PlayStation 3 and PlayStation 4. The game is slated for a spring 2014 release, and will serve as a prologue to Metal Gear Solid V: The Phantom Pain. Release details can be found here.