People use Opera knows about alternatives.
Opera have lot of + than – … which make them keep Opera.
Opera slow on HTTPS sites but it can opera 20 windows and each window can have 20+ tabs.. that is stability. Also some features in some sites do not work. But encounting that kind of problem is rare. Also with Opera you need back up browser.
I do not care what browser you use but I do really doubt any other browser can do 20(windows) * 20 (tabs) = 400 tabs. I do not lie it can use up to 5 GB RAM + (at-least it did for me) if you get there.