I've read several of Cameron Pierce's other books so far, and Gargoyle Girls of Spider Island is my least favorite of the bunch. It's not a bad book, it's just different from the other ones I've read.
This book is very much bizarro horror. A bunch of college students get stranded on an island that's inhabited by beautiful looking, green women. Unfortunately, these women turn into horrible monsters that get their sustenance by raping men. As you can imagine, this leads to a book that is bloody and full of disturbing sexual imagery.
Basically, ths book isn't for the faint of heart. It's still a good read.