First, you are probably a man. Unless you want to create your own harem you will have to combine your resources with other men for access to their wives (that no longer want them) and/or their daughters. This means a hierarchy and just getting into it, unless you saw God and Jesus and they empowered you to start your own group like the guy in Manti (TLC) you will be in a pecking order for the hens.

If you happen to be a woman, the big pro is that if you happen to like your sister wives you have one of the best support groups on the planet. The con is you have the most intrusive group of women to deal with that you've ever had. Also, you have a pecking order and when the dust settles the "First Wives Club" is a reality. They win backed up by the men.

Good luck. "The Principle" almost always requires "The United Order" in some guise or fashion.