Hursthouse is a big fan of Aristotle (although she does "update" a few of his sexist remarks), and often hearkens back to his discussion of "the virtues," and the idea that there is no set of rules that can ever properly encompass every situation -- rather, the ideal virtuous agent is someone who is actually _skilled_ at ethics, and simply knows the virtuous thing to do.
An example that might help get across the idea of virtue ethics -- take a classic ethical case such as Ayn Rand's example of a man whose wife is very sick and who spends extraordinary amounts of money to save her life. It turns out, however, that he could have spent the same amount of money and saved the lives of ten women he didn't know. The utilitarian says that the lives of ten are more important than the life of one. The virtue ethicist says that the fact that we place the interests of loved ones above the interests of strangers is good -- a vital part of humanity we would not want to sacrifice to some mathematical moral calculation. And who would want to live in a world where we forsake our spouses to save strangers?
The book also contains a very interesting chapter on naturalism in ethics. Overall, a very worthwhile read, especially if your entire background in ethics consists of Kant, Bentham, Mill, etc.
A note -- this is not the most abstruse philosophy text I've ever read, but I wouldn't suggest approaching it without some sort of academic philosophy background.