Another random point if you are into Credit Cards/signup bonus/churning:
Hyatt and Marriott are both direct transfers of Chase Ultimate Rewards. But Hyatt points are worth significantly more, so it is much easier to augment your Hyatt points balance with Chase points.
Breakfast difference when traveling with Family:
Marriott is for up to two people (lounge, or continental if no lounge).
Hyatt is for up to two adults, plus two children. And in practice, they pretty much always seem to reimburse all children.