I guess APPEND Sweet :)
In my opinion, whoo is the most adept producer at tuning Append Sweet. His music is, well, somehow the opposite of keeno's, based on how each producer uses and harmonizes various instruments (whoo tends to compose more "complicated" music?), but interestingly this piece of music is rather different.
The album is a collection of songs from 14 Vocaloid producers, and it is truly worth listening.
Title: And Your Bird
Vocal: Hatsune Miku Append
Album: Lifework
Year: 2011
Track number: 2
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