My opinion is that the poly community embraces an idealistic experience which, more often then not, fails to materialize when human emotions enter the equation. To your questions then:

Conceptually, and in its idealic state, I think that it is a wonderful lifestyle with the potential to create a platform that promotes personal and spiritual growth. In practice, it more often than not is emotionally predatory in nature and does much more harm than good. While I think that the idea of monogamy is part of our social programming courtesy of the combined force of both early church and state, I think that most people fail to take into consideration just how powerful social programming can be.