Well as a voice for the busty onee-san camp i have to say... I don't like her either! I don't really know her character so i can't say anything about that but her appearance just isn't appealing to me and I'm actually surprised that she seems popular. While i prefer bigger boobs, I still think that the bust size should be somewhat proportional to the body and hers are just too big for her body to be attractive.
Shamefully though i have to admit that I like her Scene. Without going into too much detail it has more attributes than just being dominatrix-style. One thing for me is also that I just can't stand this virgin-pain talk which way too many Scenes have so I almost have to be happy about a Scene where this dosn't happen.