I haven't been able to get ahold of any chapters past 11 but from what I've read so far, this manga is very enjoyable!
While this is definitely within the shoujo manga category, I think that its mystery elements make it much more interesting than a typical shoujo series. Although the nature of the manga is episodic, there are already hints in what I've read of the overarching plot regarding Shiho's past and how she is growing as a character. In addition, I like that the main romance changes both characters and therefore, creates an interesting relationship.
Overall, this is a great shoujo read and
may even be interesting enough for the guys!