In essence, this is a quite classic romantic anime. What makes it a bit better than other animes of the genre is the larger than usual cast of characters, and the fact that it actual features two lead pairs.
The characters themselves are also quite classic, but a few twists here and there prevents them from being too predictable.
The anime also has the usual flaws of the genre: too many "Oh, it's nothing" lines at times, characters conveniently catching deadly colds from rain, etc.
Still, the double pair of leads saves the show, perhaps because it gives it enough density to be entertaining.