[trextrex]

I use Opera quite extensively, and have been, starting from Opera 7 or so. There was a brief gap in my usage during the time when Opera switched to blink and a lot of the old features were missing, but now it is pretty much back to feature parity (at least for the features I care about).

I think (IMHO) it has the most usable UI and apparent performance. It has nice built-in features like ad-blocking, mouse gestures (including rocker gestures), some nice single key shortcuts for moving around tabs. The V7 tabs extension [1] provides a really good experience for vertical tabs. It has also sufficient customizability, full compatibility with Chrome extensions.

I am aware that all of these are possible in other browsers, and I do use Chrome/Firefox for non-trivial amounts of time for various reasons with all equivalent customizations, but Opera just seems so much more usable and performant for me across platforms, although I can't put my finger down on one single thing that makes it so.

Edit: I have to say I'm really liking the vertical tabs on the new Vivaldi and their new features. Maybe I'll try making it my primary browser for a while.

[1] https://addons.opera.com/en/extensions/details/v7-tabs/