This book is touted as Science Fiction for people who don't like Science Fiction. It's really only Sci-Fi because there are aliens. This is a romance novel. A chick flick with aliens - kind of like her other books that are chick flicks with vampires and werewolves.
This is an updated version of Invasion of the Body Snatchers. It is primarily told from the perspective of one particular "body snatcher" named Wanderer. She has now entered her "host" body, formerly known as Melanie, on her 10th planet. Melanie is reluctant to give up her body, however, and Wanderer has to put up with having another voice in her new head that doesn't want to stop talking.
After Wanderer sees enough replays of Melanie's happy life with her true love, Wanderer falls in love with him as well. She decides she no longer wants to do her civic duty and rat out Melanie's family because she loves them. She (and Melanie) ditch the alien police and try to hook up with Melanie's family.
It's not a bad book, it's just not really science fiction (except a couple of parts). It's a very romantic drama in which most all the bad guys either get what's coming to them or change their evil ways. Also, only a few token good guys die which, considering the circumstances, is a very romantic look at this possible reality. It's a good sized book but it only took me 3 or 4 days to read.
Apparently this is being made into a movie so you should for sure read the book first so you and I can both be annoyed by whatever changes they decide to make in order to get this into standard movie format and length.