I am a FF user. It is an excellent browser for many reasons. Personal preferance is a big reason, but there are others that I won't bother to try and convince anyone of; try it for yourself.
I am not sure, but I didn't see any mention of portable FF. At work, the admins have IE loaded and that's the only browser installed on our workstations. I put portable FF on my USB Flash Drive, applied several pipeline changes, turned off caching, cookies, etc. Now I can use FF at work with all it's neat features, like Web Developer, Weather, Skins, etc.