Opera used to be a fantastic web browser, with a custom high-performance Presto rendering engine and features like tabbed windows that didn't show up in competing browsers until years later. However, the modern Opera browser is a shadow of its former self, reliant on chasing trends and meme advertising to
I also left Firefox for Chrome many years ago during that time period, but Firefox has been good again for quite some time. They did a big refresh called Quantum several years back and solved most of those issues. Give it a try.
They also solved the “issue” of XULRunner and all associated functionality, not offering anything instead.
I had to move from
conkeror, and now jump between FF and SeaMonkey. The latter lags behind a bit in porting FF functionality.To each his own, I guess.