Objectively, I'd say it's probably FFT for being a richer game with more to development than raising points... but Disgaea's almost like candy, you can just belt it down fast, and find some trick to grinding super fast and abuse the hell out of it. So, I only ever beat Disgaea properly, but did watch FFT through to its end.
Now if only FFT could have FE's speediness or at least its fast feel, and it'd be perfect.