We loved both seasons. The second season is definitely different than the first, since it's the story of the rise of Lorenzo the Magnificent. Is it entirely historically accurate? Well, it's television entertainment, so -- no, of course not. But the major beats of history are there. The major event points happened.
I actually like the idea of a season being a generation for this dynasty. And that much of it is shot in Tuscany gives a great feel. I love the scenes shot in Rome. I realize they weren't going to really know what the colosseum looked like in the 15th century, but it was a good reminder that it was OLD then too.
The other thing I think the storyline does well is to give you some insight into the power of the church during that period, and the reminder that the pope really functioned as its own king/emporer, with his own army. The expansion and power of the various banking interests were in support of the expansion of commerce AND the power of the church as it extended across Europe.