There is an unboxing and gameplay demo here:http://www.youtube.com/watch?v=LDaLLjdsuFU
It is noted as being compatible with the downloadable PSP games so the following list of titles should be available to play from the outset:http://en.wikipedia.org/wiki/List_of...able_PSP_games
Those are more expensive than iOS apps but aren't too badly priced. I'd expect the Vita titles to cost more though. Going by the above video, they seem to come in retail boxes too so not download-only. The Vita has an SD-card type port.
The Vita looks like a solid gaming machine - effectively a portable PS3 - but who knows what size of market is left for that kind of device. I imagine the 7-12 year old range would be the biggest target as the 12-30 range would opt for the 360 or PS3 and it's certainly a decent alternative to an iPod Touch.
Some parents would look at it like buying an iPod Touch + a PS3 for $250, which is decent value. It has the advantage of having immersive games. If you give a kid an average iOS game (excluding e.g GTA 3, Tomb Raider Guardian), it will be completed in an hour tops and they need another game. Some PSP games can easily last 6-10 hours.
I don't like the UI but it's functional, there isn't much info about apps yet but at least it has a semi-usable browser:http://www.youtube.com/watch?v=BV2AAUf-oIY
The PSP browser was unusable. The Vita browser isn't perfect though - no Youtube support it seems, nor decent HTML 5 support but I guess they can add this in software updates:http://exophase.com/34618/ps-vita-do...ut-of-the-box/
Tactile feedback is fairly important IMO for a good gaming device. I don't like iOS for gaming particularly. I found the PSP worked better but lacked good titles worth buying. My preferred setup is the big console/PC + iOS for casual games.