There's a lot about how this is worse than the SNES version, and in general, I would agree. However, there are a few things where there are improvements, and it will be hard to go back from those.
1. Items have more interactions. The magic boomerang can cut bushes and tall grass. The fire rod and lantern can burn bushes. The silver arrows can break pots. It will be hard to go back to the original from these.
2. The flippers allow you to briefly dive to avoid damage.
3. There is a warp point added to the top of Death Mountain once you unlock Turtle Rock, which is amazing. The hookshot shortcut in the Dark World, east of the castle crossing the river, is also more obvious.
4. The Ice Palace's layout has been slightly altered to make it much less of a chore.
Finally, there is the 4 Sword Dungeon. This is a counterpart to the Tower of Ganon, featuring a boss rush of the first 4 dark world bosses, but with new abilities, and finishing off by fighting Shadow Link. This is a GREAT dungeon that finally gives the Cane of Somaria and the Cane of Byrna their due. If only you got something for completing it, like the 1/4 Magic Meter upgrade, I would consider it essential.
So overall, if you were to play 1 version, you should play the SNES. The screen crunch on the GBA nearly ruins the game, and the sound is awful. However, if you're familiar with the SNES version, and are itching to replay the game, there's a lot of fun new stuff here.
1. Items have more interactions. The magic boomerang can cut bushes and tall grass. The fire rod and lantern can burn bushes. The silver arrows can break pots. It will be hard to go back to the original from these.
2. The flippers allow you to briefly dive to avoid damage.
3. There is a warp point added to the top of Death Mountain once you unlock Turtle Rock, which is amazing. The hookshot shortcut in the Dark World, east of the castle crossing the river, is also more obvious.
4. The Ice Palace's layout has been slightly altered to make it much less of a chore.
Finally, there is the 4 Sword Dungeon. This is a counterpart to the Tower of Ganon, featuring a boss rush of the first 4 dark world bosses, but with new abilities, and finishing off by fighting Shadow Link. This is a GREAT dungeon that finally gives the Cane of Somaria and the Cane of Byrna their due. If only you got something for completing it, like the 1/4 Magic Meter upgrade, I would consider it essential.
So overall, if you were to play 1 version, you should play the SNES. The screen crunch on the GBA nearly ruins the game, and the sound is awful. However, if you're familiar with the SNES version, and are itching to replay the game, there's a lot of fun new stuff here.