I've currently got the 4gb card. Thinking about buying a new 16 gb card so that I can actually save some games to the thing. I've got a Persona 3 (PSP) save that I want to transfer to the new card. PS plus doesn't allow cloud saves for PSP games. Any ideas how I can transfer the save? Don't want to have to switch cards every time I want to play P3.

There should be PSP saves stored in the 'PSP Utility' section of the transfer tool app. Just transfer that to your PS3 or PC and load it over onto the new card.

Content Manager should allow you to transfer them to PS3, and then you transfer them to your new memory card. That's how I my PSP saves on the device in the first place.