Pro's and Con's to Foster Parenting?

We have twin 5yo girls and an 18mo old boy. The stipend for the girls covers them pretty well - we get much less for the baby and it doesn't really cover his needs at all. We figure the 3 kind of balance out and it's managable. The state also gives us some reimbursement for mileage and covers daycare when I'm at work, and all the kids medical is covered by medicaid. We love working with the kids, even with their challenges. Working with the state is very frustrating, and the stress has actually affected my health over the past couple of years. Everyone says we're making a difference in the lives of the kids we have come through here, so we hope it's worth it.