Just got hit with AF from the last of my 100k bonus cards from last summer.
I had canceled the rest but wanted to keep this one open for the lounge access.
I called South Dakota and got a very nice retention offer -- $50 statement credit for every month of the next 7 months in which I spend $1500.
Of course, the MS will probably end up costing me me $125 of that $350, so the retention offer is really like paying $450 up front in order to get lounge access, $225 in statement credits and 10.5k miles.