Gotta say I’ve been using Firefox for years as my daily driver and it has been great. Maybe it is because I’m running on higher end machines for the most part, but I’ve had no complaints with it across Linux, windows, and Mac.
I've also been using it for several years and almost completely agree with your sentiment. The only areas that have given me trouble are in the dev tools. On my machines the debugger is significantly slowed down when opening very large JS files, source maps compound the debugger slow down, and I can't always inspect variables' values when using source maps (possibly a build tool config problem).
