The Elder Scrolls

This.

Ulfric may have his flaws, but in a time of war there likely isn't a more experienced and capable warlord- the kind of leader the alliance would need its members to be if it were to go toe-to-toe with the Dominion. I have a hard time envisioning him not getting buddy-buddy with Hammerfell if he manages to seize Skyrim.

As much flak as it gets, I think Bethesda did a phenomenal job making this a tough and controversial choice. Both sides have their merits and flaws.