Just some quick updates... the usual emails that you get when an offer is used never came with this one, and many people (myself included) reported that the statement credits were slow to post. (Lots of feedback on DoC about this.)
I can now report that I've received the credit on two of my cards. I moved forward with making a purchase on my third card (Everyday) and expect to see the third credit probably the first of next week.
My first two statement credits were triggered by an AT&T Prepaid reload card (physical card) and a Hulu e-card (email delivery). My third purchase was a physical Sam's Club gift card; it hasn't posted yet but I don't expect to have any issues. 
