Q. What are the advantages/disadvantages of Forms Personalization when compared to CUSTOM.pll?

A. Advantages:
Personalizations are stored in tables rather than files
Will not have a bigger impact when you upgrade or apply patches to the environment
Can be moved easily through FNDLOAD from one instance to other
Can be restricted at site/responsibility/user level
Easy to disable/enable with click of a button.
Personalization will store who columns with which we have the ability to track who created/modified it where as in CUSTOM.PLL we don’t have that ability.

Disadvantages:
Not all can be customized using Personalization.