It's also on some international flights now.
DTW/BOS/ATL/LIM LIM/ATL/BOS/DTW was $980 in coach and $1,320 up front. No brainer seeing the ATL/LIM portion is delta one with flat beds and the ATL/BOS flight is a 757 with cradle bed seats. The MQM's alone are worth paying for the upgrade and being able to save the GU for a more expensive flight