Vocaloid Song Recommendations
http://www.youtube.com/watch?v=Hv0_5M1b8N8
^Sonika singing "Recado," a Portuguese song.
Sonika was advertised as being able to sing any language with a bit of effort. She even had a variation released in China (no songs have been made that I know of so far, actually...) Of course, most songs featuring Sonika (or any Vocaloid truly) feature her singing in English or in Japanese. So the fact that's she's singing in a different language is a nice change.
I can't comment on pronunciation/enunciation (one of the main complaints associated with her voice), but I can say that she sounds pretty good here. The beat of the song is nice, and her vocals are pretty smooth and nice. So it's not often I say this, but this is a Sonika song that I want to download~ Her voice sounds very nice here!
http://www.youtube.com/watch?v=Yt1mJcsVDyg
^Lily singing Beautiful World (a song from Evangelion)
Lily's trial version was released recently, and so many songs featuring her voice were released. Some of the songs sounded okay. Some made her sound like an UTAU with triphones. But this cover features her voice extremely well. It plays to the voice's strengths (deeper notes, as opposed to high-pitched notes) and her voice sounds smooth and human.