I was a long-time AMEX Gold cardholder until two years ago and carried a large Membership Rewards balance by using it as my primary card. I cancelled the card about two years ago to focus on Alaska Airlines miles. I do not carry any other AMEX cards. I'd get an occasional offer from them to renew various flavors of their cards but this was the first offer that made me rethink. I was actually going to accept the 50K offer before the deadline in June but the 75K offer showed up in time. I also received the same 50K offer at the same time under a misspelled "alias" of my name, so I guess I was just on the right list.