PSVita supports multiple PSN Accounts per system, but only if you have multiple memory cards.

[superchunk]

So for every PSN account you have, you have to buy an overpriced SD card? Nice.

Still, with a portable device that really should be used by a single person, I don't see why this matters. I know I'd end up buying multiple for my kids if I had to buy one.

Reason why we have two DSi, they are personal use items. Not like consoles.