Well this seems more of a promotion for IE11 and windows 8.1, but the benchmark for firefox 26.0 was 10.59 sec. And the music drives you bonkers.
I couldn't run the test in IE at all. The button to click for starting the test was non responsive and never did anything.
In Firefox, I got a message that this browser wasn't compatible and I should install IE 11.
In Opera, the sound didn't work.
I have to agree with David, another MS promotion which in my case backfired....