You seem to think Firefox is still at version 4 or something. It is now heavily multithreaded, has sped up considerably (and is now competitive with even Chrome for most users), uses far less RAM (even compared to other browsers), and has even had its process sandboxing improved on most OSes.
None of this is an attempt to deter people from switching, but simply to fight your misinformation. It's popular to bash on Firefox lately, while telling users to switch to Chromium. But Opera is probably a better choice for users who don't want to opt into Google's services and just get the faster and leaner browser, and it is better-poised to return to greatness than stagnate like Chrome has lately.
Because it is!
Sounds like Windows 3.11 and MacOS classic all over!
It is snappier yes but only if you do not run more than a tab or two. It is time to move on as it is obsolete at this stage and is the new IE 6 of this decade. Stale, obsolete, and insecure.
Firefox while it does work is not the best and it pains me to type this. Chrome works better on my older cpu with mulitcores. Maybe on a shiny new icore3 Firefox might seem snappier on lightloads?
But the architecture is dated, insecure, and can not handle modern gpus and multi core cpus with modern security of per tab processes like IE and Chrome had since freaking 2009.
Shoot even the recent IPhones and Galaxy phones have 4 core systems. It is 2014.