It's mostly Marriott properties for me, though that's been more about the properties themselves. Either:

• I'm staying in areas of places like Washington, DC and London that are dominated by legacy Marriott properties, so I often find better location / price with the Marriott ones, or
• The legacy Starwood properties where I'm going (that are in my desired feature / price range) have tended to be Sheraton and Westin properties that are old and tired. Once they get some investment and some TLC, they could change my mind.