Two hours until the end. My final prediction is that Spartacus and his generals die protecting the slaves, while they get into the hills and go free. But lots of slaves will die.
After the credits, Spartacus meets his wife, Oenemaus, and Crixus, and they welcome him to the afterlife. They tell him he fought well and died with honor.
According to historical accounts, the slave revolts brought virtually no change to Roman society. There was never a slave revolt again, after the Romans crucified enough slaves to cross the state of Arizona (not sure if they'll show that).
The writers will want to show some sort of victory (which is the name of the episode), but since they are sticking with history, it will a personal victory. The victory of freeing some slaves, living (and dieing) as free and self-determined people, and meeting their loved ones in the afterlife as a reward.
And by afterlife, I mean Elysium and not Hades.