I bought and sold several PSP and they never really worked for me, missed the 2nd analog and the games weren't very good IMO.
Was preordering ME3 tonight and saw the Vita display model and gave it a try.
Its a sweet piece of hardware. Screen is big and looks great, the sticks are actually sticks and not nubs like the PSP. Load times were quite slow in several games but once loaded they looked great and played nice and smooth. 4GB proprietary memory cards cost $20, and I hear the battery life is only 3 hours when playing games.
In the end I was tempted but decided not to buy just yet. Like the PSP, the games just weren't anything I was interested in. Hope it doesn't go the way of the PSP - there is some potential IMO.
I caught a webcast displaying the Uncharted game for it, and it looks fantastic.
I have no use for a handheld, but if I can run it HDMI and use a regular PS3 controller with it, there looks to be some titles coming up for it that'd make it worth picking up.
I had a PSP back in the day, and the clunky game discs + long ass load times on just about everything (holy fuck Tiger Woods was AWFUL) just sucked.