I bought 1 PSP, did not play it much, so sold it. Then I again felt like I wanted one when they released Remote Play with the PS3. Still was not playing it.
So overall, I guess I'm not much into handled gaming. And as much as I want a Vita because it looks cool, I will resist buying it.
I was the same as you, I had a PSP and DS. I never played either systems, but I've already played my Vita more then the other 2 sysytems combined. Theres so much content which is either cheap or free (PSP games, PS1, Demo's, Occasional free software like Ecosystem and now PS+) its hard not have something to play on it, maybe not the AAA experience I was hoping for yet, but I'm sure they're on their way. Being able to access all games at all time with the 32GB memory card is probably one of the most important things for me and up until now the 3DS didn't didn't have its big titles availble for download.