With only 2 main reservations...err make that 2.5, I give current Opera v.44.0 a big thumbs-up. Good features, great efficiency, good if not great speed, good stability.

The 2.5 caveats:
1.0 Bad default on font scaling makes fonts pale and fuzzy if not fixed. - This is an older problem come back to haunt but fortunately has an easy and very effective fix.
1.0 Even in Private Mode, all attempts within Opera to completely clear the Internet Cache fail. Try it yourself. Happily Ccleaner can do it. I don't know the cause, and would like to report it to them but see no way to do so. It partly cleans up, but always manages to leave anywhere from, say, 8MB worth of junk to quadruple that.
0.5 I never have trusted Opera for Bookmarks. They don't seem to be concerned about it. If you import bookmarks, they will be botched somewhere somehow. If you rely on Opera to keep them, then MOVE them to the next machine or whatever, good luck. You'll only lose the ones you found the most valuable

Those aside, I use it, I like it. Even at 1080p running dense videos, it is very lean/mean and looks good if the first issue above is corrected.