My work deals with understanding cooperation in humans. Since social interaction has a moral element, I have been ineluctably concerned with philosophical ethics. Although I studied a fair amount of philosophy in school, I did not study ethics, and I feel I have a rag-tag grounding in this aspect of modern philosophy. This is why I obtained Sober's undergrad textbook, which is really an intro to all of Western philosophy.
This book is nothing like my own introduction to philosophy, which consisted exclusively in reading excerpts from the great philosophers of the past, accompanied by the professor's lectures, which went 'way over my head. Now, my background was in math and physics, and I never read the classics in those fields (you need a dictionary to understand these old guys, and their notation was usually horrible). Sober's text is so refreshing! In each of the major areas of philosophy (he doesn't deal with logic, philosophy of science, philosopchy of mathematics, and other specialized areas) he provides a lucid overview as well as a critique of the various views and his own assessment of which is correct and which is not. I agreed with him almost 100% of the time, and I found his analysis quite cogent and lucid.
The bottom line is that this book is excellent both for beginners and those who want to brush up. It is also a great read.
Sober's treatment of ethical philosophy gets five stars for exposition, but only three for analysic and critique, in my view. I share Sober's deep appreciation for Aristotle and virtue ethics in general, the major attraction of which is its self-characterization as a set of principles for leading the good life. Virtue ethics thus avoids the utilitiarian/deontological problem: why should we be moral? For virtue ethics, moral behavior is its own reward, the main problem being (a) have the fortitute and self-discipline to behave morally, and (b) figuring out exactly what the moral thing to do is. If this view is correct (I think it is) then the ethical theories of the past few centuries, virtue ethics aside, are completely misguided. As to the content of morality, Sober correctly criticizes Aristotle for thinking that virtue is unitary, when in fact his own conceptual framework is more consonant with the view that there are many virtuous paths, and virtue is in part culturally specific.
Recently, there have been serious efforts to answer the question as to the content of morality by treating moral discourse in much the same manner as communicative discourse: there are some basic organizing principles, but basically there are many different moral discourses and our job as scientists is assess their comunalities and differences, as well as modeling how moral discourses diffuse, expand, contract, become extinct, mutate and emerge, etc. In this sense, ethical theory should be like linguistics, where the structure of valid utterances are deduced from social practice, not by the idle intuitions of professional philosophers. See, for instance, David Wong's Natural Moralities: A Defense of Pluralistic Relativism.