This is a rather broad and open question, and your answer will depend a lot on your own opinion of Kingsolver's works. However, I think personally that Kingsolver is a very effective and accomplished writer. She is one who has written a wide range of texts, from a story set in the heart of Africa in Poisonwood Bible to her own family's experience of living by eating only food that they could grow or source locally for one year. She has also written extensively about issues of identity, especially focusing on identity with relation to indigenous people of America.
What is so fascinating about her as a writer is that she comes from a background of science and Biology, and this is something that often permeates her writing, whether it is in the lush description of the jungle in Africa or the matter-of-fact prose that she writes in some of her non-fiction. She is a writer who is as intimately concerned with nature and the environment as she is with issues of identity, and every work that she produces is well-crafted and makes its point effectively.