I have one. I absolutely love the screen on it. Nicest screen of just about any device I've used. But most the software at the moment falls into the DS's 'must use every single feature' gimmick. I've pretty much had mine since 2 weeks after launch, turned it on for an hour to try Katamari and haven't touched it since. I'm hoping when Gravity Rush comes out in the next couple of weeks that I'll have something worth playing. But until some better software release for it, it's pretty much collects dust at the moment.
I got one the other day, and I'm absolutely in love with it. If you haven't used it much, that means you haven't played Super Stardust, which I honestly think is the best game on the system right now. It's only $10. As far as the 'new feature' gimmicks, those gimmicks made Dynasty Warriors Next the first in the franchise playable and enjoyable for me. But I digress...
Buy Super Stardust. Now.
ALSO, coming soon (Summer, I think?) JET SET RADIO is being ported to the Vita with new touch controls for tagging (!!!!!). Can't wait.