So far it's the 3DS for me. Haven't seen anything that really grabs my attention on the Vita, other than Persona 4 Golden.
I'll be getting the Vita in due time, but with Mario Land 3D, Mario Kart 7, Paper Mario, Dragon Quest Monster Remake, Mario Tennis 3D, Fatal Frame 3D, MH3 3D and KH 3D, my handheld needs are satisfied for the moment.
Current PC Build
CPU - i7 8700K 3.7 GHz (4.7 GHz turbo) 6 cores OC'd to 5.2 GHz with Watercooling (Hydro Series H110i) | MB - Gigabyte Z370 HD3P ATX | Gigabyte GTX 1080ti Gaming OC BLACK 11G (1657 MHz Boost Core / 11010 MHz Memory) | RAM - Corsair DIMM 32GB DDR4, 2400 MHz | PSU - Corsair CX650M (80+ Bronze) 650W | Audio - Asus Essence STX II 7.1 | Monitor - Samsung U28E590D 4K UHD, Freesync, 1 ms, 60 Hz, 28"
