To be fair to Vivaldi's fans, that browser (while also too bloated for me to use) does steer clear of a lot of the criticisms leveled against Opera here. The author is a Vivaldi fan, so I imagine they're all coming from a genuine place. Specifically:

Modern Opera ships with a wide range of built‑in features that extend well beyond browsing. Sidebar messengers, crypto tools, media enhancements, and a generative AI assistant are all part of the default experience.