My position is that polygamy should be tolerated, but not celebrated (or recognized by law). My reasons:

1) It will probably lead to a shortage of women, as some men hog all the women for themselves. Women are more willing to share a man than vice-versa. (Whether this is cultural or biological is irrelevant. Either way you'll end up with a shortage of women.)

2) Poly marriages are not as stable as two person relationships. The more premises an argument has, the less likely it is to be sound; so too for marriage. Dan Savage says that he's been to number of "poly weddings", but has never been to a poly tenth anniversary party.