Middlemarch is widely considered one of the greatest English-language novels, the equal of Moby Dick and Ulysses. It is not plot and characters that make masterpieces; those essentials ultimately matter less than use of language and the quality of the thought, two things that cannot be fully equalled on screen. But this Middlemarch is about as good as it ever gets.
Consider this sentence from Eliot, about a vain young girl in the presence of a man she wants: "Every nerve and muscle in Rosamond was adjusted to the consciousness that she was being looked at." Reading that, you feel it. Or this, about blind love: "Strange, that some of us, with quick alternate vision, see beyond our infatuations, and even while we rave on the heights, behold the wide plain where our persistent self pauses and awaits us." I could open Middlemarch at random, to any of its 800+ pages, and find sublime observations like those.
Andrew Davis (writer) and Anthony Page (director) obviously cherish Eliot's book. The tone, the pace, the mise-en-scène in England and in Rome-- all of it is superb. The principal actors, Juliet Aubrey, Rufus Sewell, Douglas Hodge, and especially Patrick Malahide bring it all to life, aided by an ensemble of British actors, most of whom were known to me because of their distinguished careers. (There are weaknesses, of course, including two young actresses, Trevyn McDowell and Rachel Power, who are just good enough).
I've read Middlemarch three times, and watched this series twice, between readings. Perhaps the greatest compliment I can give it is that the praiseworthy incarnation of Eliot's characters actually served to enhance the 2nd and 3rd reading of her remarkable novel.