I have tested this page out in IE6 and FireFox 3 for comparison. What I see from both of these browsers is pretty much the same. I could not distinguish any differences. I'm including a screen shot of what I see in IE 6. I'm not using IE tester but a native version of IE 6, here are my stats:
update versions: SP2; 3283
I did notice that it took a second for the images to load for the sub nav as I was hovering over them but that was not any different than what I experienced in FireFox.