That he has. My test clip choice was inspired by him[1], and I also link to another blog post of his[2] in the conclusion. That VP8 blog post is almost three years old now, though, and the comment I'm replying to in my article claimed that VP8 is better than H.264 "at this point". This is why I did my test with the latest and greatest encoders available for both formats today.
[1] http://forum.doom9.org/showthread.php?t=154430
[2] http://x264dev.multimedia.cx/archives/472