If you already read something by Yamamoto then you can expect basically same experience. Do not misunderstand, themes, thoughts and story is actually pretty fine, It's just how Yamamoto works and blends various parts it creates his distinctive style.
Three individuals, weird organization, almost uninhabited island and various peculiar tasks. Even interesting mix of ingredients can turn to be complete rubbish if you cook it wrong. Fortunately, this isn't that case. One of the most interesting parts of this piece is presentation of "trust". Characters trust completely everything the organization says to them. On the other side, reader can't (or at least shouldn't) trust absolutely any information whatsoever.
Beside "trust", Yamamoto touches themes of "love, humanity and self-knowledge". At some points one can see paraphrase of Adam and Eve. Interestingly enough, It's depicted in a way that you can't be completely sure in what position "Adam and Eve" are. Are they trying to get to Eden Garden? Or maybe they're already in it. You can really think about this story if you want.
Drawings are nice. Classic Yamamoto again, nothing surprising there. And yes, there's quite a lot of sex. If you think you can take it then read this piece. No worries, this isn't some idiotic mindless porn manga.