Sony has been hyping the connectivity options between the PS Vita and their console lineup and are set to make it even more pronounced with the PlayStation 4. Remote Play will enable players to stream their PS4 games to their PlayStation Vita via WiFi. It's been touted since the PlayStation 4′s announcement and now we have some more details of how it will work through the Ultimate FAQ.
But it seems there are some hiccups. For the best result Sony recommends that the PS4 and the PS Vita be connected to the same WiFi network and that the PS4 be connected by an Ethernet cable and not wireless. It's kind of cutting down the dream of leaving your PS4 on and gaming while on-the-go through other WiFi networks. It will not work over a 3G connection.
Sony also says that they "expect that most PS4 titles will support Remote Play" which means it's up to the discretion of the developer and or publisher of the game and may not be supported if it is either too costly or difficult to implement.
Honestly, it sounds like a more complex version of what the WiiU is offering out of the box. It frees up the TV for something else, but you end up having to sit on your couch anyway to play.