The answer (as is always the case with these questions) is it depends. Do you plan to use points for the top end properties or low end Hamptons and Fairfield Inns? I would recommend u check the LoyaltyTraveler blog, I think the author recently addressed this question in a very comprehensive manner. Also keep Gleff's recent observation in mind - SPG is a good program except for the very top high end hotels which require absurd # of points.