The Casual Vacancy and I did not get off to a good start. The abundance of characters was difficult to keep track of for a while. And I had an initial impression of stilted writing and forced "adultness": an entire early paragraph is devoted to describing someone's breasts, and most of the penis references seemed jammed in.
Once I was able to mostly remember who was who, I started to sink into the plot(s) and the feeling of stiltedness vanished. The characters were marvelously varied and believable, often exhibiting minor embarrassing/shameful/dishonest behaviors that made them feel that much more real. The book reads like a study in human motivation; I loved that aspect of it. Hell, 20 years ago I WAS one of those characters. It was the last thing I expected from J.K. Rowling.
The characters might have benefited from just a tad more restraint...there seemed to be somewhat more screaming and yelling than was entirely necessary. But that's a minor complaint.
The Pagfordian history and politics were reasonably complex, completely credible, and critical to the main plot. And every character's personal plotline fit together with the Pagford story perfectly. I was impressed (and a little relieved) at how well everything clicked. I honestly did not expect to like The Casual Vacancy anywhere near as much as I did. Four and a half stars.
Note: It's not a very happy book. I expect it's going to get some backlash for that.