I am honestly baffled by the negative reviews for this show. While it wasn't perfect, for me the good far outweighed the bad. First, the strengths:
1) The soundtrack! The opening sequence is strong, and sets the tone beautifully for what is to come, and the moody instrumental music throughout the show added to the scenes without being distracting. 2) The entire thing is visually stunning. Seriously. From the landscapes to the sets, costumes, food, colors... the whole thing is a feast for the eyes. 3) Medici: Masters of Florence is a study in the dynamics of both a family and a city. If you enjoy political intrigue, relationship drama, or the arts, this show is where it's at. 4) The acting in this show is beautiful. Annabel Scholey's many layered performance as Contessina was stunning. Richard Madden can say more with just his eyes than anyone currently on television. Stuart Martin and Guido Caprino as Lorenzo Di'Medici and Marco Bello own the screen with their charisma.
I only saw two issues that detracted from the program. 1) The casting of Dustin Hoffman as Giovanni was a real head-scratcher. His accent and demeanor did not mesh with everything else, and the performance had the air of being something his agent forced him to do. Normally I really do love DH, but this was not his best.
2) This quality is a little harder to put into words, but I felt like the show took a while to find its footing--like it wasn't quite sure which direction it wanted to take. In spite of that, I couldn't stop watching, and really enjoyed this show. Looking forward to season 2!