Marriott, hands down, no contest, for several reasons:
1.) Their are Marriott hotels nearly EVERYWHERE, name a city, and there are 2-3 different brands compared to Hilton, Starwood, etc.
2.) Marriott points take a smackdown on Hilton. Example, I am staying in IAD for a quick layover, the cheapest Hilton is 30,000 points for the night. A nice suite at Towne & Suites Marriott is 7,500 points. VALUE????
Marriott hands down!!!!!