When i first read this manga i was intrigued by the plot. To be honest, based on the style of drawing (giant eyes, bishies etc) i expected a low-brow predictable shoujo. Well, i wasn't too far off, i mean, from the first chapter alone you could tell what was going to happen, 'secret' identities and basically all the major pairings. But, regardless, it was enjoyable, if not a bit creepy towards the end.
The low-down;
Art - Passable at a 8 (for shoujo art, but i would round down to a 5 for general aesthetics)
Although there are giant bug eyes and excessive blushing involved, it's not too bad and there weren't any major flaws like hideous lopsidedness or anything.
Plot - 7
Intrigueing to say the least, i wish it was explained a bit more but obviously that would trigger a landslide towards sci fi and i don't think the writing would have supported anything less superficial.
Other deductions
-0.5 for the how fast things moved along. I enjoy shoujo but it bugs me how quickly characters fall in and out of love and the degree to which this manifests itself in their behaviour. Some acts of affection are cute and whatnot but others border on psychopathic and i wish shoujo mangaka's knew where to draw the line.
Final word -
If you enjoy shoujo this would probably be in the upper range in terms of quality but it's still rather predictable.
It's not really incest so don't get put off by the tag.