Writting this right after finishing the reading, so might regret later. Anyway...
This story is good...? I mean, the plot is actually very good, but it's slow, so don't expect any steamy hotness so soon. The one-shot at the end, though, is what throws your happiness levels through the roof.
Main story - THE PROS: the way the characters think is actually pretty realistic, and Waki, the protagonist, is the definition of persistency. Also, the characters from the other story, Chiisana Koi no Melody, appear constantly, and you get the good vibes from that story as well (if you read it, of course. If not, you'll just find them cute as hell). - THE CONS: the other main character is a drag, and you'll want to punch him in the face even when he's right. Also, the pacing is sooo slow, and full of obstacles, that any other normal person would have given up halfway. The feelings of the main couple seem one-sided the whole time, and it's hopes are always fed by the mixed signals the teacher sends.
Side-story - THE PROS: It's awesome. The pacing is perfect, the events are well-placed, and the characters are very relatable. At one point one would start wondering "what's happening with all this well-goingness??" but don't worry! The action and the feels are real in this one! - THE CONS: it's one-shot, so if you want something to entertain for long, you'll have to re-read it a thousand times in a row.