This article is from the Final-Fantasy and other Square Soft Games FAQ, by email@example.com (Nick Zitzmann) with numerous contributions by others.
It's all up to you.
The Ragnarok Sword is definitely a good sword - it uses MP to do
critical hits on enemies, is ultra-strong, and randomly casts Flare on
However, with the Ragnarok Esper, you can convert enemies into items,
and the bearer of the Esper will learn Ultima, the game's most powerful