VITA easily. Hands down. Without question. I'm not a fan of the 3DS. Vita is like the SEGA Saturn of handhelds. It's so full of great hidden gems. From Uppers. Macross Delta. Soldner X. A ton of RPGs, Action games that are console quality. Of course, there is also Persona 4 G and Gravity Rush. Thankfully the RPGs don't have that fucking hideous Chibi shit 3DS games have. A lot of Mecha games on Vita as well. 3DS sure it had SMT IV and DQVII on it but for the most part, 3DS was such a boring, lame system for me.
VITA is still a class-looking system. Wonderful screen. Dual analog. The only real downside was yes the memory cards. That's the one area 3DS wins. There is not a day where I'd choose 3DS over Vita.