Glad I'm not the only one. I want to love this doujin--I really, REALLY do--but Reina felt so OOC, to me. Not the Taki bits: I'm all for a character being in love with someone else while discovering an emerging love with another (b/c that's REAL), but she was so... expressive, facial feature-wise. Some of the things she said also felt... off. I don't know if it's different in the novel (forgive me, if so), but Reina's rarely that 'smiley' in the anime; and strong emotion only comes when she boils over.
As for myself, I found it interesting for Reina to be acting out of character. I know her personality and was aware that she would not do the stuff she did in this doujinshi, but it is still fun to imagine what could have happened. That's one of the fun things about doujinshi in general for me.
But what I really wanna see is a reversal with Kumiko being the true S.
Oh that terrible personality of hers...