This is my fourth favorit Honeyworks song as well as one of my favorit Rin and Len duets so far. Classic. It's an old one with some poor tuning, but the song itself has really shaped the VOCALOID industry and its personification of the libraries.
This is one of my favorit Regulus songs as well as one of my favorit Megurine Luka songs. I remember listening to this just a few hours after it was released.