I saw the first several episodes when it aired and enjoyed it (we had a couple of months of the Showtime movie package for free at the time). It *seemed* to be historically accurate for the most part, given my limited knowledge. The cast was good, characters compelling, scenery, etal, pretty good as well. All in all I liked it.
I will caution you that there's quite a bit of nudity/sex, so if that's not your bag, well this may not be your show.