I've received, and used, 2 Amex DL Platinum certificates for my wife. Saved me a total of $1,100 in airfare.

The key to these deals are flexibility in travel days and the all important minimum fare requirements. Any coupon that requires the purchase of a full Y fare is not a deal because of the abundant number of apex fares.

If you are talking buy one, get one free international business or first class that's another story. Even then, I personally couldn't see purchasing a $12,000 F full fare to get a companion F seat.