Just an observation that Citibank Cards currently have a $720 money back offer at Wellcome on Fridays, Saturdays & Sundays over the summer (at $60 per week through a transaction of $500 or more). ~10% off beats pretty much any miles deal.
http://www.wellcome.com.hk/en/offers_new.html

(This following the Amex 10% off for bills of $800 or more on Saturday or Sunday in June.)