I used Opera desktop for something like 10 years too. When I moved to Chrome (maybe 3 years ago?) I was like, "ah, this is what these websites are supposed to be like". I was actually quite sad to say goodbye and I still miss a lot of the features (sidebar!), but it always struck me that Opera was living in a bit of a dreamland where they just hoped the web was 100% standards compliant. Admirable, but unfortunately (in the short term at least) users suffered because so many sites just didn't quite work. This may have improved since I jumped ship.
If a major company could give Opera the resources to catch up to Chrome in that area, then I'd be excited for the potential to create a comprehensively market leading browser.