Empire gets a pair of crappy mines and a tiny hard to defend town with no walls, and the Rebels get a fortress city, with a major silver mine and capture of it that alllowes them to unify the south of Skyrim under one banner, meaning no broken supply lines and a clear "front" to attack on and plenty of silver to buy supplies and arms with.
Ulfric calls me a traitor, says I have given the empire the tools it needs to win the war. Are your serious Ulfric? Can you fail anymore as a commander and tactician?