Is this prominent undergrad text on ethics a worthy guide to how to live for an otherwise decent non-fedora-wearing-evangelist atheist? Is ethics really that complicated? Does Rachels hold up without going down a rabbit hole?
Not at all. It's not a guide at all. It's a quick introduction to popular philosophers and figures. You're meant to read the essays and make decisions on which ideas hold up. It's commonly used because it creates opportunities for discussion.
Rachels herself does well. I don't remember thinking he was getting off-track or off the rails at any point