Summary: Ridiculous price. SD cards offer similar speeds for much, much less. That one is required to get one of these overpriced monsters to properly use the Vita, after already dropping a significant sum on the device itself, is beyond infuriating. I'm liking Sony less and less these days.
Summary: Unless you're going all physical with your Vita games library, you'll need more than a 4GB card. A PSP title is roughly 1 - 1.5GB in size. Downloadable Vita games come in various sizes, ranging from 500MB to a few gigs. Then there's the Minis titles and when Sony releases support for PSOne titles as well, you'll be needing all the space you can get. Especially if you want music, photos and videos on your device as well.