You can't go wrong with either. Both consoles have solid lineups of RPGs. They're both backwards compatible (Vita digitally) so you get access to their predecessor's lineup as well. I'd go with the Vita since it has the greatest JRPG ever made. Though you can also get it on the PS2.

hmm, 6.5 is a higher than I would give it, but it isn't the blindly in love score that a lot of people on here seem to give it.  Let me ask you this, is the story in Etrian Odyssey 4 good?  The combat looks good to me, but how is the story?  

If we're not counting digital, the 3DS by a long shot, thanks to it's backward compatibility.
Ignoring physical backward compatibility, it's close, though I still prefer the 3DS (Vita's a bit more niche, but there's some really good stuff there too).
Factoring in digital, probably the Vita. There's tons of (J)RPGs on PS1 and PSP, and Vita gives you digital access to most of these. 3DS has some good stuff in it's eShop, too, but 3DS Virtual Console is still very lacking.

Personally, I prefer the 3DS, since I don't like digital. That's why I bought a PSP and a PS1 for their respective games. My 3DS has ultimately made my DS lite useless (except for the ability to play about 3 of my import games that the 3DS can't play), and thus I'm factoring in DS's library, too, while the Vita has to life off of it's own available-at-retail software.

if you play recent games: 3DS. But if you buy retro games: Vita (you can buy some gems from PS1/PS2 era)

I don't own a Vita, but I've been very pleased with the RPGs on the 3DS so far. Shin Megami Tensei IV, Tales of the Abyss, Bravely Default, and Fire Emblem Awakening have eaten up way too much of my time (80-100 hours each). There's also Pokemon if you're interested in that, and full backwards compatibility with the DS's huge RPG library.

More recently, I've been having a fun time with Bravely Default. I highly recommend it, if you're looking for a turn-based RPG. The fighting system is fun, the story is interesting, and the grinding is really streamlined. If you're unsure, there's a great demo on the eShop, it's what pushed me over.

Hmmm, I would prefer that to having endure all the crap in bravely default, but it probably isnt for me.  RPG's are all about story for me, so thanks for the info!

PSP by far.

I feel your pain... I wanted to love this game as one of my favorites, but the forced extended story just made it a pain to play... I'm just going through the last chapter to get that true ending but it isn't that fun anymore.

3DS is superior in terms of current content (Bravely Default and Fire Emblem Awakening alone put it ahead) but the Vita is catching up fast, and I believe it'll take over the 3DS as the primary JRPG console soon, with games like Demon Gaze (kind of like Eterian Odyssey) and Conception II (kind of like Persona, just a little more niche) coming out soon, along with excellent games like Ys Memories of Celceta and Persona 4 Golden already out. I personally would go with 3DS for the current selection, but if you are willing to let the game market mature I would go with Vita. Or, get the best of both worlds and get a 3DS now, and get the Vita a year or two down the road.

Note: If you want to get an OLED Vita (superior screen), you'll have to get it now though, they are being discontinued. The LCD screen of the slim isn't that bad though, so it's nothing to worry about if you do go witth the 3DS.

Edit: I personally find myself playing my Vita more than my XL these days, but Bravely Default is my favourite JRPG since FFIX, forced extended gameplay or not. Plus Bravely Second looks like it's gonna kick ass.

Most the RPGs on Vita are stuck in Japan.