Above all, it's important with federal loans to avoid default. If you default they add 25% to the loan balance. Some of these newer programs basing your payment on your income are very important to avoid default. There are differences among the programs, about a half dozen of them.
You want to make sure you fit in the right one. Some of them include your spouse's income as well. There are ways to exclude that.
There are different limitations as to what loans are applicable to what income based programs but overall they're very good programs. They do have debt relief, so after a period of time, the remainder of the debt is forgiven.