I recently booked a family of four an economy award from Miami to Buenos Aires with their Membership Rewards. It was an interesting award that I think demonstrates the complexities and fun of booking with American Express points.

I won't talk about that award specifically, but I'll use it as a jumping off point for discussion since it illustrates a typical Memberhip Rewards situation.

American Express Membership Rewards are valuable because of their ability to be transferred to dozens of partners. But they have a glaring weakness: they don't have a top-tier Star Alliance transfer partner--US Airways or United.

Membership Rewards can be transferred to Singapore, which is great because this is the only way to get into Singapore business or first class.

Membership Rewards can also be transferred to Aeroplan and ANA.