Money isn't really a problem, and I find more value in the downloads ($50 at $5 each for 10 NES games and $40 at $8 each for 10 GBA games I never got that are about as advanced as SNES games) than $80.
But in the end, the question is: "Will I keep playing it more than the PSVita?" Let me count the features:
Vita: 2 analog sticks, one HD screen, 2 touch areas, Uncharted and (hopefully) inFamous, LittleBigPlanet 2.5 and Mod Nation Racers, and WiFi.
3DS: 1 analog rotator, two Wii-graphics screens, 1 touch area, NES games and (some) GBA games I missed, Super Mario Nostalgia Binge 3DS and Mario Kart WITH GLIDERS OMGGGGGG 3DS, and WiFi.
Sorry, Grandpa Ninty, but I got a new definition of fun.