Firefox still has features that I consider absolutely necessary, that no other browser has ever had. Chrome is good, not great, I still use it. And I wouldn't use Safari if you paid me to. (I would use IE but only if paid. )
Chrome had 2 big advantages over Safari until last summer: speed and a combined address/search bar. Safari finally fixed the latter, and on a Mac, it's a stable, quick browser. Firefox is fantastic when I need to download a YouTube video (Potter musicals FTW), but I use it for little else. My web browsing needs just aren't that demanding.