Wish I would get one of these - only way it will get me to use the card.
I put $25k on the card immediately in Jan/Feb for the 10k Preferred Miles and then only use the card to pay taxes on award travel for the 5k mile discount the rest of the year.
I received the mailed offer for up to 2500 bonus miles in Q1 2013 (2 miles rather than 1 on certain spending). I have received a few of these during 2012, but never a 15k one.