There are still issues with Firefox but you are correct about people maybe not knowing. I tried it a few years ago before the speed update and it felt unusable. Nowadays it's a little more sluggish than chrome on certain things (JIRA for one) which perhaps is just a result of people optimizing SPA for chrome.

It is VERY important for people to give things a try with and without a proper ad blocker. Any browser gets WAY slower and buggier when it has to deal with the nutty page takeovers with autoplay videos and javascript running.