It was a good story. I loved it albeit the portrayal of the rivalry between the two sisters seemed exaggerated. Sensei (Ryuu-chan) was mature as for Ageha, she was cute and sincere. Ryuu-chan is probably one of the best authentic male leads in shoujo mangas.
I might add that the mangaka managed to reveal in this story , the inner thoughts and the insecurities of all its main characters and she provided a male character who is ever loyal and considerate towards the girl he is dating. He might seem frivolous, superficial and flirtatious but beneath all that there is someone loyal in love.
Papillon