User blog:Tsumou/Creating VOCALOID Music. Who is best to use?

I want to really write VOCALOID songs that are very calm, deep and piano based. But I don't know who to use! I want to either use Crypton or Internet Co. VOCALOIDs, even though I know there are many other good ones too (IA, MAYU, SeeU, Luo Tianyi, etc.). The songs will be Japanese, but I just need to decide which vocal I want to use.

Who should I pick? ( ・◇・)？