Here are my results...keep in mind everyone's mileage will vary depending on processor speed, ram, etc.
Firefox 0.8, Mac OS, 1.00-1.09GHz (34.82 seconds)
Explorer 5.x, Mac OS, 1.00-1.09GHz (60.01 seconds)
Safari, Mac OS, 1.00-1.09GHz (57.2 seconds)
Note: Opera 6.2 or OS X never got past the second test, even with popups enabled. It just hangs. Also, it jumped past the first test without even displaying anything.
Has anyone looked at the JS they're using? Is it properly written, or are they cheating towards one particular browser? I've noticed all the top 10 results are from Opera 7.2/7.5, and all are in the 5-8 second range. That seems pretty far-fetched to me! Particularly since the Average Browser Results table shows Opera 7.2 at 19.69 seconds, and Opera 7.5 at 22.25 seconds, average.