About the art, it is indeed very breathtaking. Although the ecchi classification there are only a few scenes that are hot. Most of these moments are in the bathtub, some masturbation and "staging to sex", but nothing too hardcore.
The author has done a good job in putting together several controversial themes in this work. It's that kind of manga that makes you rethink how things are. After all, the philosophy behind the manga is magnificent. If you like manga with romance, ecchi and seinen themes, I highly recommend you read "Kodomo no Jikan".
