The adoption experience is subjective. Some couples may leave the process with many a battle wound and story while others may leave with nothing but warm fuzzies toward agencies and birth mothers. Therefore, the pros and cons of adoption are varied and may or may not ring true for one's own experience.
There's no truth about adoption that can be laid out as universal as the process is easy to customize based on each party's needs. This is perhaps more of a pro than con of adoption. Prospective adoptive parents and birth mothers can decide how and with whom they work with.
The con of adoption for some couples may be the loss of a biological child. While some couples find that they can physically have children after adopting. Infertility is certainly an emotional con of adoption.
A pro of adoption is that children of unplanned pregnancy, poor home lives, and with special needs are given the loving, supportive home they deserve. Adoption, for all parties involved, is a second chance.
That being said, post-adoption can be a challenging facet of adoption. Birth parents may begin to wonder about the adoptee, an adoptee may begin to wonder about his or her pre-adopted past and genetic medical issues may present themselves in a previously healthy adopted child.
When it comes down to it, adoption is not too different from a biologically related family. And that's neither a pro nor con of adoption.