As a 3DS "fanatic" myself, I can confirm that the Vita is superior for gaming.
Vita is more powerful, higher res screen, has TWO capacitive touchscreens instead of one, two proper sticks instead of a sliding pad and a cheap "Thinkpad" "nipple", and feels better in the hand.
But Sony should go fuck itself for those expensive proprietary cards... I had to steal one from my Sony camera...