The browser that's has Google Analytics integrated, comes with pre-installed third-party tracking app, and that reports home every UI interaction you have? No, thanks, I'll stick with Iridium.
[1] https://spyware.neocities.org/articles/firefox.html
...which was last updated may 2018.
As long as there are no missing security updates, I don't see how it's a deal breaker.
...which was last updated may 2018.