To state a few obvious points:

1. I am not sure what world exists where you can trade in a used 3DS for a Vita.
2. There are way more games available for the 3DS, and way more games scheduled for release on it.
3. The quality of games on 3DS is higher than on Vita; just look at review scores.
4. Saleswise, the 3DS is solid, but the Vita isn't looking like a system that developers might consider supporting by sometime next year.

When it comes to RPGs, I would hazard an educated guess and say that the 3DS will succeed the DS in being the top platform for the genre this generation.

kupomogli
"With the 3DS, .... there's, well, nothing really."

O_O

please tell me you are joking...

If your into Persona and Atlus games, nows the time to ditch your 3DS since their having a 50% off sale on Persona 1,2&3, Crimson Gem Saga etc etc etc.

Just saying :p

crimson gem saga is really good! I'm havin a blast with it right now

If he's into Atlus games, he should probably keep his 3DS, or at least until Etrian Oddyssey IV, SMT: Soul Hackers and Shin Megami Tensei IV come out.  There is also an unnannounced SMT: Persona game apparently in development as well.

Well, there's that too. BUt with the Vita he can go play persona 1, then 2, then 3 and then 4 lolololol! but if i had the money i'd want to have both systems.

I'd argue that the PSP was king of RPGs last gen and if you've not had a PSP or played the RPGs, the Vita is a great place for them (much nicer screen) and so Vita is already the main handheld RPG system at the moment IMO.

I'm honestly struggling to find much on 3DS though I do need to get Kid Icarus. (Already got Mario 3D Land and Mario Kart along with about 12 other 3DS games).

The Vita sadly isn't much better right now, but I think to say the quality of games are better on 3DS is just plain wrong. There's nothing on 3DS that can touch Uncharted, Unit 13, Wipeout, Gravity Rush etc. Just like Sony currently has nothing to touch Mario 3D Land. But depending on the genres you like. I think most people would actually find more of interest on Vita than 3DS, and this is coming from a life long Nintendo fan.

if theres a genre the DS mastered, that was rpgs
PSP had far less and most of them were action rpgs

Maybe that was a US thing. (Europe does tend to miss out on a lot of games like that, especially in Europe) RPGs seem to be far more prominent on PSP in Europe. But fair enough, shows what I know :)

Well if you want a Vita for more games, good luck; the next game scheduled for retail release is about 4 months away (November 2nd), and it's a Need For Speed game.