Which one was it? I hope not anything with Devil in the title, otherwise you're not getting their best. Not even close.
When Eric said Nocturne was the best JPRG of all time, I bought it. And I agreed. The 120 or so hours I put in flew by, and the atmosphere, music, and originality are unmatched. NOTHING comes close to the vibes I got from Nocturne and the world they created. The game kind of scared the shit out of me in a way. I loooove the main theme for the Amala Network (basically hell), I went out of my way to download it and put it with all my music. Really chilling.
Having that said, Persona 4 is my favorite thing from them, though I don't think you would like it. (I'm a big Azumanga Daiho fan, go figure) The Persona games feature a shit battle system, extremely bland dungeon crawling that isn't rewarding in the least, but the social link aspects of it truly moved me. I never cared more about characters in my life. The sense of humor was great, and damn if it didn't go from making me feel genuinely happy (I'm a miserable fuck, that's a rare thing), to even teary eyed at one point.
Sorry for all that, as you can see I'm very passionate about Atlus. They left me with no desire to ever play or replay ANY Squaresoft game again. (Except Chrono Trigger)