Well, I just bought it the other day and it came this morning, and wow is it good. I must say, I still can't get over the art, same person who did Dance in the vampire bund, Nozomu Tamaki so you expect quite a bit when that name comes up. The story's actually by Kent Minami and as far as I can tell, this person has never released anything else, could be wrong.
Props to the translators and proofreaders for leaving in "Onee-Chan" instead of changing it to sister.
The story itself is intriguing and definitely worth buying if you haven't already. Of course I can't say much it's only volume 1 but, it's got potential, I'm just looking forward to November when Volume 2 comes out.
The spoiler below isn't really a spoiler, but I've put it in one in case people are planning on buying and don't want any little bits of information. Though in case don't read the spoiler if you haven't already read the manga.