I'm an NYC based GM who has a ~50% UG success rate. I've had an option for Economy Comfort on every single flight, though dont always take it if i'm already in a nice exit row thats not too far back on the plane.

SDS has been used many a time and has resulted in significant cost savings (ie booking the 7am flight that was $100 cheaper but going standby on the 10am flight).

Delta has bent the rules for me on several occassions, notably when 3 friends and I were headed to St. Maarten, one of them realized the week before we were supposed to leave that his passport had expired. Delta waived the change fee for all of us so that we could travel to Puerto Rico instead.

I can think of one flight i've taken this year where Delta was, and yes I paid the extra $125 to take Delta to Phoenix vs US Air/AA (NK is always cheaper but i wont fly them). I've easily gotten more than $125 of value from being a GM.

And as people like to say here, GM sucks, so i can only imagine the perks of being DM.