Always used firefox, then switched to chrome for a year, now back to firefox.

Right now, Firefox's speeds are actually better than chrome's. Also, firefox works better for slower computers/people that like doing more than just browsing the web at one time, because Chrome re-loads all of it's libraries for each tab you have open (That's why each tab takes close to 100MB of RAM) where firefox only opens it's libraries once, and still has better speeds than Chrome.

Also, Firefox has way more of the extensions that I use. Stuff like Greasemonkey, ABP, FoxyProxy, DownloadThemAll, LSACookies, etc etc.