FireFox is a good browser but also depends on the computer.
Earlier this year, I was running an old Pentium 100Mhz that I had useless but a friend need it. Internet Explorer 6 was working ok. After I heard that firefox was much faster, I installed on that computer (64BM RAM).
The result was no good. Firefox ran very slow because the memory requirement.
Talking about Linux, I am writing this on Firefox too, because there is no internet explorer for Linux. I haven't found any firefox advantage in comparison internet explorer. Even so, when I click on a existing tab on internet explorer 7, the address bar is ready to enter a new address as select the old address just to be replaced. In firefox I have to double click on the existing address to get rid of it.
I haven't tried Firefox on a good Windows machine yet, so that will be the next step. I have heard that the add-ons can be a security issue on Firefox though.