This show is definitely my thing. Let's divide it up by seasons the way Funimation does. The first season begins in an uncertain atmosphere, darkening the audience's mood and revealing only parts of Ciel's life two years after the meeting with Sebastian. We get to know the characters and how they interact with each other, then some 5 minutes on the introductory video we see Ciel naked with a red cloth and he seems to be talking with a crow. The story, however, is leisurely paced with the focus being on the characters and their conversations.
Others exist only to provide the needed comic relief. Bardroy's cooking disasters, Finnian's failed gardening attempts, and Mey-Rin's clumsiness does add some humor, but they are too one-dimensional. Even Tanaka, who is different from them and has a weird look, is not noticed much for a long time. The main characters are Sebastian and Ciel, who are fortunate to be better than the blundering crowd.
Ciel seems to be an egocentric child in spite of his sophisticated environment. On occasion his decisions does not make sense to others but the decisions seem rational for him. His lust for vengeance, though understandable, seems like a rather worn out cliché that could have been written in a way that was not so predictable.
Sebastian is my top pick among the other characters because he is so self-aware and smart. In contrast to Ciel's habitual mumbling, he would be dealing with all of the issues with ease. Others might say he is too perfect – a typical Mary Sue. However, his indomitable expertise and his resemblance to Ciel's father appeal to the audience and thus add substance to the narrative.
It has an atmosphere similar to Spice and Wolf, where the conversations are of the political nature and set in the Victorian era. However, it has more action up front which keeps the show interesting. The animation stays pretty good, but does not try to create something special or unique, which is a common feature of the era. The CG parts are rare and look good as they blend well with the natural elements and do not go overboard. The hue does not stay drab, but, at the same time, is not oversaturated.
The Japanese voices are good. Some characters' voices feel forced, like May-Rin and Bardroy, but Sebastian's and Ciel's voices hit the mark. The music is a standout, with a dark J-pop opening contrasting the sweeter ending, providing a perfect balance to the show's darkness.