Playstation Vita or Nintendo 3DS?

I'll only buy one, but im undecided as to which. My favorite genre is action RPG / RPG, although i do enjoy certain FPS's and third person shooters. My favorite game series is Fallout, including the originals by interplay as well as those published/ developed by bethesda. I've also thoroughly enjoyed many nintendo first party titles and exclusives, especially Mario and Animal Crossing. From your own opinion, and considering my preferences, which system is better for me, and in general?