Firefox is superior to Chrome on any computer that isn't low end and requires the little bit of extra speed Chrome gives.
Even in situations where I need a very fast browser I still wouldn't ever use Chrome. Maxthon is much faster than Chrome and doesn't have Chrome's terrible interface.
Chrome: Simple, light, and fast. I will use Firefox from time to time, but just because I am forced to. IE's only purpose in life is to download Chrome.
I used to use Firefox as a main till they had that firewall scare. I guess there was a bunch of holes in Firefox that were going unpatched. I switched to Opera as my main after that. Then just kind of fell into Chrome somehow. Chrome's my main. Tor is my secondary.
P.S
They patched the holes in Firefox shortly after I uninstalled.