I've only played Kingdom Hearts 3D and Pokémon X on mine. I bought Fire Emblem Awakening and SMT IV last year for the $30 e-Shop credit and I haven't gotten even an hour into either. I only buy games these days for the sake of having them, not to actually play them. Everything seems so stale and boring, but that could just be my shitty mental health talking. :/
Vita is much more worth it in terms of having a variety of things to play imo, but I don't use my Vita, either. Haven't turned my PS3 on in like a month, and my 360 has been gathering dust since around October.