As the summary stated, this manga is based on Mikito-P's song Sarishinohara.
For people who are not vocaloid fans, or never hear the song before, don't worry. There's no need to listen to the song in order to understand the manga. Beware tho, for those who hasn't listen to the song yet, and plan to read the manga: don't listen to the song and its sequel. It's pretty much a big spoiler. But since the first page of the manga already exposed the event turn(not sure if this is the right term), I guess it wouldn't hurt too much to watch the PV.
Ok, first. The art. I love it. It's simple, not overly realistic or childish. If you love the song PV, there's a high chance that you'll love the manga art. As for the story, its sweet and somewhat gentle (?). Expect a few cliche here and there, but overall its enjoyable
The character (and the dialogue) is, by far the best thing in this manga for me. They are flowing naturally, and I could actually imagine someone to say it, something quite rare in non-slice of life manga.