I echo what CSD said. The Gilded Sword is worth it (it really doesn't take that long to get once you first beat Snowhead!) - you keep it forever provided you save after getting it, it does (4x?) the damage the Kokiri Sword does, longer reach, and is well...a really good weapon to have. The Great Fairy Sword is a 2 handed C-Button item that honestly isn't as effective due to loss of shield, although it does 4x the damage of the Kokiri Sword vs the GS' 3x damage of the Kokiri Sword. Overall, you will find that getting the Great Fairy Sword is more of a hassle than a reward because you get it at the 4th dungeon which is also the second to last provided you are aiming to also get Fierce Deity's Mask...