The pilot had a couple good points I liked the scene near the end with Crassus training on the Gladiator in front of Tiberius. And how he purposefully sent the messengers by Spartacus' camp so they would get caught and Spartacus would kill Crassus' competition. I know little of the actual history so I have nothing to compare it to..
The broad occurrences are historical, and the broad political competition which hindered the capture of the slaves was real. And the fact that there were problems with house Batiatus which led to the revolt in the first place are real. The series' pretty much fill that in with detail that's completely fictional though. We know what happens to each of the historical figures, so what's fun and interesting is to see what they do with the invented ones. That and the details they make up along the way.