I love my Firefox. So in order to love small businesses you have to use the software made my a megacorporation that bullies small businesses on a daily basis and runs them out of business...interesting concept.
Dude, the NIPOMA Institute said it, not me!
Really though, you think pages display properly in Firefox but it's not really the case. FF makes less available to developers by way of it's incompatibility with certain code and functions. There are a number of simple HTML tags and values that no longer work in the latest FireFox version, and a number of other variations in the way it reads code -- some of which can be fixed by having two versions of a page (one for FF and one for IE) but many of which simply limit the functionality and dynamics of the page in Firefox.
Really though, i don't like FF because it costs so many people so much unnecessary work and money to not have a universal standard on the interwebs. That and i hate that it makes me update so often...
but then... i'm usually on a mission to find porn and can't spare the time.