ELECTROCUTICA - Crystalloid
This is Electrocutica's third album, featuring Vocaloid voices Megurine Luka and Hatsune Miku.
I think twice before listening to anything Vocaloid, especially Miku, since they're pieces of software that are VERY difficult to manipulate correctly.
Sure, people might write a few songs and have the software sing, but fine tuning the voice to produce the best (most realistic / softest / most mature, w/e) pitch of voice is something that not all composers can do.
In Crystalloid, VOCALOID vocals sound crisp and clear, clean and vibrant. Miku's pitch isn't ear-shattering, in fact, she becomes closer to sounding like a real human.
As for the actual music, if the circle's name didn't give you much of a hint, yes, it is purely electronic music. Mixed electronic sounds with a software voice. If you like this sort of thing, then this album is probably what you're looking for!
High-quality preview here:
http://www.youtube.com/watch?v=9dTWGRMDyeI9 Tracks. Check out Electrocutica's two other albums if you're interested. They also produce original music with human vocals.