I would pick Steve Young. I liked the way he played the game. I also like the way he treated other people outside of the game of football.
Young is lucky he beat Favre in that 1998 wild card game.....the Packers had Young's number for years....
Packers fans insist to this day Jerry Rice did fumble. Nonetheless I give the edge to Favre despite belonging in prison for criminal embezzlement of public money. While Favre doesn't matching Young's efficiency nor mobility, Favre defined the modern day gunslinger archetype. There's a reason every cannon-armed QB since from Matt Stafford to Justin Herbert to Pat Mahomes has drawn Favre comparisons. Likewise while Favre benefitted from playing with stellar players from Sterling Sharpe to Ahman Green he never quite had the offensive talent which surrounded Young (most notably in the form of
noted stick-um user GOAT WR Jerry Rice
I will die on the hill that Moss is better. Finally there's something to be said for the ironman streak while Young's mobility resulted in concussions ultimately shortening his career.
Ultimately it comes down to longevity vs. peak and while Favre's numerous playoff chokings in the latter half of his career weigh him down it's hard to not side with the more complete body of work.