Quote Originally Posted by ReloadPsi View Post
Since the defensive stats make such a superficial difference to the damage received in this game, Evasion is way better. My party is almost constantly outfitted with two Mystiles (50% Evade, 60% Magic Evade) and the Aegis Armlet (15% Evade, 50% Magic Evade) whenever possible. The latter is less effective and also has fewer Materia slots, so I give it to the party member with the most HP.
Evasion is less important in the face of many attacks in the game, simply because most of the more notable, "Big Damage" attacks tend to be auto-hit. Defence therefore is important, though to reach the maximum of 255 the large majority of it comes from Vitality. Then again if you have 255 Vitality (probably a bit lower) the defence on your armour won't matter, so knock yourself out.