I know this has been asked a lot. I've using a jpn psn on my ps3 since i bought the system. I bought a vita bundled with games on amazon so i have to use my us psn to pair with the system. I really don't mind earning trophies on two seperate psns, but i'm encountering another problem. Vita is essentially region locked, why? You can play JPN games, but you cannnot download online pass, DLC, even updates, that makes the whole region free completely useless. I know sony is doing this for business reasons. I'm just going to keep on waiting for the support for multiple accounts in the next update...
@devil240z: Even if you buy a disc based JPN game, you still don't get to download online features. So I guess I'm gonna buy another vita someday...Take my money sony!!!
Oh well that sucks. PSP wasn't like that but then again PSP games didn't have much online stuff or even patches.
It doesn't make the region free thing "completely useless" so much (I was able to play Persona 4 Golden months before it was released in Australia thanks to games being region free), but yes, only being able to use one account per memory card is a total pain.