Minecraft on PS4 will feature worlds 36 times bigger than the ones you might be used to on PS3
Scheduled to be launched via PlayStation Network this August, Minecraft for PS4 will include all the features from the most recent Playstation 3 version, plus bigger worlds and a greater draw distance. Players with Playstation 3 Edition or Playstation 3 + Vita Edition saves will be able to import their worlds to Playstation 4. However, you won't be able to transfer your saves from Playstation 4 to Playstation 3/Vita due to various technical issues. Furthermore, cross-platform play will not be possible between Playstation 3 + Vita Edition and Playstation 4 Edition. On the other hand, many (but not all) DLC skins and texture packs you've purchased for Playstation 3 Edition will be available for use in Playstation 4 Edition.
Minecraft: Playstation 4 Edition will cost $19.99 but if you've bought Playstation 3 Edition from the Playstation Network you will be able to upgrade for $4.99. The upgrade offer will last at least one year after the release date.