It was unfortunate that the Vivaldi owners (which includes most of the original Opera founders) lost Opera the way they did (likely financial reasons), it was their own browser, not a copycat of another, and like Firefox, a community browser. They had their own social site, email & more, since the takeover, has became another Chrome copycat, and they were openly hostile to those who asked for the original Opera features to return. Karma's hard, the current Opera is barely on the map. Last I heard from a very reliable source, Opera's bookmarking system doesn't work well, and that was the end of a long run. The new owners killed the browser, rather than let the original revive itself, a mistake made over & over by those new & thinks they have a magical answer to everything.
Fortunately, those same original owners have rebounded rather fast with their Vivaldi release, and with the addition of an email client or service, and also have had a forum for a bit, looks to be off to a hot start. No, it won't be like the original Opera rebranded (the new owners holds any copyrights to former code), yet add email & hopefully once again a community, what the people wanted, and Vivaldi at least stands a chance to rise above Opera, and maybe a few more lesser known browsers, including Chromium itself. As many computers as I've personally laid my hands on to do some work, have never seen Chromium installed on the first one, though have seen Opera (especially the older versions) on many.
Hopefully Vivaldi can be a great 2nd browser to many & even the main browser for those who likes the speed of Google Chrome, yet wants fewer ads. While I believe Vivaldi can gain some redemption over Opera in little time, it'll be a long uphill battle to even think about competing with Firefox or Google Chrome, though Firefox has been on a slide as of late, if they drop the Flash plugin for the 32 bit browsers as reported (for all versions), some users may look elsewhere, if HTML5 for 32 bit proves to be not popular. Bearing in mind, they have very little incentive to pour cash down the drain on lesser used platforms. HTML5 is for the future, not the past.
I too believe that Vivaldi is a lot more than a browser wanting to wallow in the shadow of Chromium (or Google Chrome), have no doubt that once the smoke clears, Vivaldi will be a known name to many Linux users (as well as Windows users to a lesser extent) & there's even a Mac edition, and will likely end up in many Linux distros official repos with Opera getting the boot. Really this should happen anyway, it's a shame that Opera 12.16 is still being offered to 32 bit Linux users (more like a sick joke), should be removed & replaced with Vivaldi, which stays current.
The Vivaldi team has primed themselves for success, have done it once before & can do the same again.