I am marking this bug as closed: unable to reproduce.
Really, though, you should do a little more testing before you try to go public like this. This code renders almost the same for me on all three browsers: http://i.imgur.com/fmEhGOB.png
Seriously? There are slight differences, but nowhere near the same extent as evidenced on OP's blog. Really, the only place I can see any difference is on the curve of the C's.
Some difference is to be expected. Google, Microsoft, and Firefox are in competition, after all. Microsoft has the advantage of controlling both the OS and the browser in this case. I would be surprised if IE did not render slightly better. As others have pointed out FF and Chrome look better on other OS's (where IE doesn't even play).
Really, though, you should do a little more testing before you try to go public like this. This code renders almost the same for me on all three browsers: http://i.imgur.com/fmEhGOB.png