>>3064682First off, the voice I guess... I got into Vocaloid first because I liked the music, and just natually gravitated to Len since I liked his voice and design. Design-wise? The banana hair, of course; but it's such a great design all around though, the eyes, the clothes, the dynamic with Rin...
And the best part is that Vocaloid in general is so focused on fan content that there is never a shortage of it, and there's such a huge amount of diversity in the art, music, etc, that explore different facets of the "character" that we'd never get to see if it was just one corporation in charge of making all the content like it usually is. This applies to all the other Vocaloids too, of course.