It's true, Firefox just doesn't work for some websites, that are specifically coded for IE. Either it won't work at all, or it will work, but look like ass. Nothing the Firefox team can do about that, without forcing Firefox to act like IE, which would then open up the possibilty of Firefox inheriting all of IE's problems.
So don't count on it ever happening. Instead, try finding websites that have the same content you want, that don't require IE. I've found all the websites I go to work fine to perfect with Firefox, so I've had no reason to even install IE with my latest format/reinstall using an nLite'd installation
. But then, I'm no surfing every concievable website in existance 24/7. I've got a core of about 20 websites that I frequent, and then occasionally I have a need to check out other sites. I haven't run into any yet, that refuse to work under Firefox. I'd estimate I've visted a few thousand unique websites over the past near 2 years of using Firefox exclusively.
My browsing habits aren't all that common, apparently. But even friends of mine that are using Firefox, don't have any problems. And they are the type that browses every conceivable website in existance. I got them to switch to Firefox, at a time when their computers were riddled with spyware, trojans, and other viruses that they knew about but didn't want to take the time to back up hundreds of gigs for a format/reinstall. Firefox performed like a champ, even then (back in the 0.7 days). Now, they've been using Firefox since then, after a format/reinstall or two, and they still aren't having problems with it.
I honestly don't know why Firefox can work perfect for some people, and be a bitch for others. I'd be interested in finding out if it's actually Firefox, ID10T error's, or something else installed on the system causing the problems.