I've never been a big fan of the Ragnarok esper. Given the choice between being able to morph a few monsters into mediocre items (ok, the Genji Glove isn't mediocre, but it's not better than the Illumina sword) and the opportunity to obtain one of the two best swords in the game, I'd take the sword any time. (Granted, the Atma Weapon is better than the Illumina if you can be arsed to level up sufficiently, but why choose between them when you can have both?) Frankly, I consider the esper to be a waste of time.