Even though it's been less than three months after the database update was released (well, technically, it was available for beta-testing for several months before its official release), there's already some pretty good songs out there. One of them comes from an artist who calls themself Captain Beefheart (I'm serious!) who made a song with a mellow drum n bass-esque song using Miku's sweet voice:
There's also another artist called bunga who's made several songs using the new Miku voices. The artist's style is more mellow than Captain Beefheart's and uses otherworldy sounds:
As for whether or not the new voices sound better when using them to say stuff in English, only time will tell. Or when I stop being lazy.