I think I've mentally disqualified her as Best Girl... probably because the glasses are assumed to be fake, and she doesn't have anything else going for her besides her stoicism. Might have something to do with her shipping habits.
Then again it might just be that the overall quality of girls in this series is so overwhelmingly low that I can't bring myself to give a damn about any of them.
"Well, I don't know why you have that kind of 'obsessiveness' (sorry, I don't know another word in English) to pick a 'best girl,' but I too was thinking Osaragi was a really shallow character. However, after this chapter, at least her way of thinking is anything but shallow. I don't know what you classify as 'quality' for a girl to have in a series, but at least the way of thinking and even the character growth overall in this series is really smooth, albeit slow, obviously because the focus is on the 'romcom.' Anyway, I don't know why you rate them so low(aside maybe design-wise?); in some aspects, they are more likable than many out there.