It might be excellent in terms of performance (I don’t know), but it’s proprietary software and based on google chromium, so I rather keep away from it. Try https://floorp.app/

Lots of people like Vivaldi for the many reasons stated in the comments. I personally feel its bloated, cluttered UI and it runs heavier on my system (compared to Helium and Ungoogled Chromium, which are both excellent browsers).

However, I daily drive Mullvad and Librewolf, with Zen for web presentations. I much rather these hardened Firefox browsers than Chromium based ones.

I should stick to Firefox forks like Waterfox, Librewolf, or Ironfox. I think Vivaldi has gone the way of Chromium as have many others.

Extensions you can run are Privacy Badger (EFF) and Port Authority.

Vivaldi is about as good as you can get with a Chromium based browser, but with the fundamental compromises that come with Chromium thanks to Google’s influence. It is European based so may have better governance and fundamental provacy than US based companies, but that is an assumption.

At the end of the day Vivaldi is a commercial browser, and that is a fundamental compromise that means it has to weigh up it’s commercial interests against users interests.

That said, I use Firefox as my main browser, Librefox for some other stuff, and occasionally use Vivaldi with a VPN extension for some stuff, and rarely Chromium without extensions if I have something low level to do on a site that I can’t be bothered messing around with fixing adblockers on. I don’t think you have to be all or nothing; it really depends on what you’re trying to do and when.

Vivaldi itself is well designed; it’s designed more for power users and tries to do everything. I just use it for browsing, but I appreciate the touches it offers. If you want to use a Chromium based browser, it’s a well made one.