The story is competent enough, the characters reasonably believable, and I enjoyed it whilst I was watching it. Having said that the almost-obsession in anime and manga with the definition and limits of humanity makes this a well travelled road, and one that is hard to truly impress with.
Worth a look but probably not a keeper.
*Apparently the term for this is "the uncanny valley" although I note that the theory is subject to a considerable degree of criticism.