I had issues with FF1(GBA) because after the dancer stopped telling me what to do, I wandered aimlessly leveling up so bad that I beat Chaos, while not paying attention, while eating at a chinese Buffet.

FFVII was my easiest, FFVI second easiest, FFIV a tiny bit harder, FFV alittle harder (DAMN YOU DRAGON!!!! *issues*), FFII hard, and FFI really hard 'cause I didn't know what was going on.

Oh and yeah FFX was easy, all the one's I didn't mention basically mean I don't like them AKA FFVIII, FFIX, FFXII (Yeah I don't like it.)