The 2 main characters are very good, but what lets it down is the support cast.
Sarah Paulson has no chemistry with anyone - so her story arcs really drag. . Hughley tries, but he is boxed into a stereotype a few episodes in and becomes one dimensional.
The network characters become bland and again a bit one dimensional.
There is some great dialog in the series and some very good performances, but as a series it it is kind of fractured, if there were a few different casting choices made and a better character backstory to some of the characters and better sketches for the show it would probably have been more successful.
I am a huge Sorkin fan, but the West Wing was a really tough act to follow so this may have colored my judgement.