One of the oldest and most heatedly debated branches of philosophy, ethics plays into everyone's lives on a daily basis. Questions of "what's right" and "what's wrong" lie at the root of most major political and personal movements. To determine your own codes of conduct, it is often helpful to analyse the advantages and disadvantages of ethics as a whole.
Disadvantage: Polarization of Society
Because it offers such an integral look into human nature, ethics -- as a branch of philosophy -- tends to create divisions among those of varying opinions. Within the United States, the reverberations of this effect are at the core of government policy. Two groups, such as Pro-Choice and Pro-Life, work from similar facts and land on different notions of what is ethically and morally "right." These rifts within society may slow down legislation and other government progress.
One advantage of any firm ethical system is that when the time comes to make a decision, there is often an existing framework for making that decision. For example, if an ethical system decides that theft is wrong in all circumstances, then any person who firmly believes in that ethical system should be able to turn away ideas of stealing. This process can expedite decision-making in general, as it has often already answered questions that may arise.
Disadvantage: Varied Theories and Constant Change
Ethics, as a whole, is a branch of philosophy that many consider to be necessarily unfinished. As technology and culture changes, new ethical issues are always arising, such as ethics within distributing content online. Likewise, issues of "cultural relativism" can create various interpretations of similar issues simply through the specific traditions of any given culture. These problems, and others, cause ethics to be a field of tumultuous change with highly varied interpretation.
Advantage: Building "Good"
The Internet Encyclopedia of Philosophy notes that ethics "involves systematising, defending and recommending concepts of right and wrong behaviour." As such, the field is, by and large, dedicated to helping derive systems for understanding and improving human behaviour. As an end-result of finding and invoking a true ethical system, the world should evolve into a safer, friendlier and happier place.