Poor series
I enjoyed the first two episodes, but the rest just dragged. Half the show is about John Adams wife and their boring corny discussions. Children grow up and you never care. It's also hard to follow which one is which except the girl. The last episode is horrendous, the story of elderly people in fake looking make up dying one by one.
There's a never a real sense of who John Adams is, because the writing is largely pedestrian, he seems to be a somewhat annoying blabberer who would so lucky to have all sorts of ideas come to his mind that history proved were right. In fact, most of the plot is driven not by characters, but by historic events. Characters just adapt to it and feel compelled to take that exact course of action.
John Adams attempts to be more than a collection of early USA myths, but largely fails. It's on the nose portrayal of slavery as despised by everyone, aggrandizing dialogue, and attempt to fit as much events of John Adams life as possible without giving it much thought puts it down.