If you mean Final Fantasy, while the other games are good quality for handheld ports, the first game sadly had its balance ruined in favour of bringing it in line with other modern Final Fantasy games. Healing items are ridiculously plentiful and you can carry far more potent ones above the basic potions you were normally limited to, petrification and death are now curable mid-battle (unlike classic D&D rules on which the game was originally loosely based, where such strong healing spells needed so much time to cast they were out-of-battle only), multitarget healing spells were made vastly stronger. Spells are nigh-infinite now as opposed to a limited resource as they use a refillable MP system with MP restorative items being easily obtained. Exp gain is also vastly increased, so the main game essentially has no challenge now outside of the bosses in the bonus dungeon (especially the ones who rely on multi-target non-elemental spells) and the final story boss (who has 10x as much health as compared to the NES version and who benefits significantly from the revamped spell damage system, thus hitting much harder with his array of unique spells).the GBA FF ports are really nice, too.
Spoiler
White Wizards can obtain a flat-out insane piece of equipment in the PSP/handheld release which basically is the GBA port + high res graphics and an extra dungeon that adds 10% max HP healed at the start of every turn, though at that point you've demolished the superboss (and 4 White Wizards are suboptimal for the new dungeon which has time limits on floors and thus speedier damage dealers and characters like Knight or Red Wizard who can use some of the new crazy equipment like Barbarian's Sword are good to have in party).