It varies a lot based on how picky you are with your choice of child. That said, a quick and easy adoption of the most available child is more likely to be followed by a life time of having a less healthy child, for various kinds of health issue.

That said, I think it is good communitarian practice to be involved in at least one adoption, as a parent or sibling. There are so many abandoned or abused kids who deserve better than what they have.