The story itself is derived from "Doctor Faustus" and the whole idea of the Faustian bargain, but it's generally very-well adapted into the Victorian setting. The first 10 or so episodes are rather good, but things drop in clarity and get more confusing as the episodes progress. By the end, some things are tied up together well, while others are left in shambles.
Character wise, Sebastian completely steals the show. With his mysterious persona, [seemingly] nice attitude and good looks (oh lordy), he's totally the centerpiece. Ciel can be annoying at times, but he is after all "only a child." I would have liked to see more development of the secondary and supporting characters, for they felt rather one-dimensional.
Art quality is very good, especially when it comes to the action sequences. OP and both EDs are very enjoyable. The English dub is quite excellent. The Victorian-style soundtrack really adds to the atmosphere.
I really enjoyed watching "Black Butler," despite the gripes I have with it regarding plot. It apparently deviates from the manga after the first arc or so, but seems good as a stand-alone watch.
