I have used Kagan's Normative Ethics, supplemented by several primary sources, for over a decade in my mid-level moral philosophy course that focuses on normative ethics. It is, in my opinion, the best overview of normative ethics available. It is not a moral problems text and it doesn't discuss metaethical issues except to clarify what they are and (largely) set them aside. It is relentlessly focused on normative ethical theory. The organization of the book is excellent, beginning the substantive discussion with theories of individual well-being. It is not just plausible forms of consequentialism that need to have an account of individual well-being. Commonsense morality, too, and many nonconsequentialist theories of morality take the promotion of individual well-being to be ONE relevant moral consideration. And deontological theories that impose a constraint on causing (or intending) harm, will need an account of harm, which (most plausibly) involves an account of well-being. So, this is a good starting place. The development from there can be seen as a very logically ordered discussion of a series of questions: Is individual well-being all that matters to the value of a state of affair from a moral perspective? If not, what other factors are relevant: equality in the distribution of well-being, preference for the benefit of those worst off, distribution in accordance with desert, merit, or entitlement? Then, is the promotion of what is valuable from a moral perspective all that matters in determining how we should act? If not, what else is relevant? Are there (non-value-based) constraints on promoting good outcomes--constraints against doing/intending harm, lying, breaking promises, etc.? If so, what is the "shape" of these constraints and how are they to be justified. If there is a standing moral reason to promote the good, within whatever moral constraints exist, does this lead to morality "demanding too much"? And, finally, then, Kagan turns his attention to moral foundations: how are we to justify whatever moral factors are relevant.
One extraordinary characteristic of this book deserves special mention. Some will find it a serious drawback; I find it a very attractive feature. In the body of the textbook, there is not one mention of any philosopher. Nowhere in the body of the book does one hear views ATTRIBUTED to Aristotle, Hobbes, Bentham, Kant, Mill, Rawls, etc. The book does, though, have a long annotated section on "Further Readings" that points students to the relevant literature. Those who want, primarily, to teach students the history of normative ethics will find this a serious drawback, though it can be addressed with supplemental reading. Those who want students primarily to engage with normative ethical theory directly, will find it an attractive feature of the book. I have students read a number of primary sources, including Bentham, Mill, and Kant. But I like the idea that the textbook that organizes our discussions is focused on the theory-space and the various arguments that can take place in that space, rather than who said what in the history of normative ethics.
I have had great success using this book and the student reception has been terrific. I routinely recommend it to new graduate students, or prospective graduate students, in philosophy who have a weak background in normative ethics.