Sez Physics Geek in the comments:
Well, I’ve been a FF user since its inception and I used Mozilla/Netscape before that. Now I’ve migrated to Pale Moon. It completely transferred everything and all of my add-ons still work. Oddly, it actually runs about 15% faster than its sire, Firefox. I should have switched earlier, I guess, but inertia can be a tough thing to overcome.
I’ve just done likewise. I wish I’d known about Pale Moon long ago. It does everything Firefox did, with pretty much the identical user interface, but much faster and with less memory use – in fact, that awful FF memory leak issue seems to be gone in Pale Moon. I’m sold!