I am a graduate student in philosophy. I have not used this book as a textbook, rather I am using it in my research in metaethics for an independent study.
The essays, old and new, provide a snapshot of the important debates under the umbrella of metaethics, including: are values real? Answers include "yes, they are real" and "yes, they are real but mind-dependent" and "yes, they are dispositioanl properties," "no, they are fictional." Is ethics a science, a philosophy, or neither? What is the relation between morals and motives? Are ethical terms truth-apt or not, and either way, how exactly do they work semantically and pragmatically?
Most of these essays you can find on JSTOR or elsewhere. The benefit is having them collected together, and selected for you. Also, the introductory essays are very readable (Shafer-Landau's style is terse and clear) and usually helpful.
The selections are insightful, exciting, and well-rounded. The chapter introductions concisely situate, explain, and critique the readings that follow and make the often challenging selections easier to understand. There are few typos and the text is attractive and easy to read (visually speaking). As a student, I am very glad to have this anthology.