I work at both a middle school and a high school. In the cafeteria before classes start in the mornigns, I see lots of kids playing around with their iPhones and Androids, and a tablet here and there (guessing most kids are smart enough to leave them at home to prevent theft). I rarely ever see a kid with a PSP/Vita/DS/3DS, and honestly, the ones who do have handhelds systems are pretty hardcore nerdy gamer types.
My 18-month old daughter thinks the PS3 controller is pretty awesome to run around the house with, but she loves the iPad. Holy crap does she love it, and we don't let her play with it very much.