J.P. tells us what makes To Heart different (with spoilers, but hey, how old is this show?):

I can’t quit put my finger on it, but To Heart has a certain something, a je ne sais quoi if you will, the prevents me from automatically hating it in the way that I generally automatically hate bishojo game conversion anime. []

My gut instinct is that the show never really feels exploitative or pandering in the way that shitty bishojo game anime are. []

Which is not to say that To Heart doesn’t try to pull on the heartstrings. It does, but it does so in a warm, organic way rather than by the calculated combination of specific fetishes. Similarly, I felt bad for Shiho at the end when she realizes that she’ll never be able to beat Akari for Hiroyuki’s affection. It feels like it’s because the show actually makes them act like childhood friends, rather than “childhood friend” being some kind of signifier which really just means that she’ll randomly show up inthe morning to wake him up, slap him because he has morning wood, give him a bento, and then walk with him to school. It’s the use of that kind of lazy signification that’s one of my major beefs with most titles in this genre.

I don't quite agree with all J.P. wrote there (in particular, in praising the Multi storyline he forgets or ignores the way Multi returns to the school to stay, which is a notable weakness of the story — unsurprisingly caused by pandering (to good-enders)). Still, he gets major points for explaining why Shiho's arc was so outstanding. It's the blogger's duty that I failed. To Heart is the only series other than Azumanga for which I have both Japanese and American DVDs, and I never explained why.