For me, J.K. Rowlings The Casual Vacancy wasn't an easy read but I developed a fondness for it.
The story started off slowly, not a lot of action in the first third. The characters of little Pagford were complex and well-thought-out but it took some time getting used to all the names, families and loyalties.
Since I've read all the Potter novels in English I noticed a difference in Rowling's language which is much more elaborate and took some getting used to (for me as a non-native reader). I liked the different idioms she used for the different characters.
And I liked that she created interesting, realistic characters which aren't necessarily likable (most of them aren't) but authentic.
Each of the characters demonstrates their egoistic and selfish perception of the society they live in. They act on their desires without caring about the consequences or willingly do harm to others around them - all this in front of the idyllic scenery of the typical small English village. Scary enough, their actions are totally comprehensible and naturally lead to desasters in Pagford's little world. The only one who was apparently different - Barry Fairbrother - dies in the first chapter, leading to The Casual Vacancy. But looking at the (non-)existence of compassion in Pagford the vancancy probably isn't so casual but permanent.
Most reviews discuss Rowling's blatant change of subject and people are disappointed that the novel is indeed not comparable to the Harry Potter novels. She chose a rather calm, unexcited topic, the setting is not very original and the plot has a few personal and interpersonal catastrophes.
So what? If you forget about Rowling and Potter you get a well-designed and well-written character and society study. There's not much action, there's no magic - but a bit of shocking (?) reality what people are able to do to other people if they only think about their own interests and needs.
J.K. Rowling, The Casual Vacancy. Little, Brown and Company, London