Averting an acute deficiency is completely different from optimal for health. I don't have a simple cite saying this amount of choline is optimal. I have an impression based on peoples response to extra choline.

Edit: to clarify, choline is not the sole reason I strongly recommend eggs. It is possible to get enough choline without eggs, but the fact that the overwhelming majority of the populace does not meet the adequate intake makes me suspect most diets don't fulfill this.