I guess I am like jabez, I'm Gold with Marriott (just missed renewing Platinum last year), Diamond with Hilton, and Platinum with Starwood. I tend to follow the offers - just took advantage of the 4 stays 50,000 points for Hilton, and next week booking Marriott for the free weekend. But, if I had to choose only one program, I would have to go with Hilton - I almost always get upgrades and being able to earn both points and miles is very nice.