I think this book is best read by going into it without thinking that it was written by J.K. Rowling. I know it's been said to death, but this is definitely not Harry Potter. The Casual Vacancy starts off with the death of Barry Fairbrother. His death was sudden and now everyone is plotting to see who will get his seat on the town council. There's a lot of politics in this book, which is probably why I didn't like it as much as I wanted to.
It's actually a fairly solid book, but ultimately not really my type of book. The thing that saved it for me where the secret lives of the townspeople. I loved those parts and hated all the political scheming. I could have read an entire book just about Krystal's family. There were a lot of characters to wade though, but I really liked the younger kids the best. J.K. Rowling has a great way of writing children and adolescent characters and the kids in this book really showed that. Their stories were just so much more interesting than the adults (maybe because there were less politics with the kids?).
Overall, it was a well-written book, but I'm not sure exactly who it should be marketed to. Most people probably like either one half or the other.