Ultimate Rewards points transfer to four airlines, three hotel chains, and Amtrak. Starwood points transfer to about 30 airlines and to Amtrak. If flexibility is your objective Ultimate Rewards is the weaker choice.
Good to know. I am considering the CS but currently have SPG AMEX. Does the 5K bonus miles on SPG transfers make the AMEX a better choice? CS is 1:1 - correct? In my case, I am only looking at the airline transfer options.