An interesting design in the same vein as Last Stand that gives you a powerful damaging option with the last health of your ally, which is usually saved for blocking a villain attack. As far as total damage output is concerned Last Stand is usually better - consider a 4-cost 2-ATK hero, or 5-cost 3-ATK hero, Last Stands uses that final hp for 1 more damage than Go Down Swinging would. But if you need that ally to scheme for the turn, or you need a bigger burst of damage, Go Down Swinging does more damage in the short-term.

Captain America is certainly the best ally to use Go Down Swinging with, and I'd be tempted to run a few copies in any deck with him. Rapid Response and Make the Call can help ensure he will be out when you draw GDS. I also like a situational card like this to tuck under Black Panther for the perfect moment when you need that burst.