Vivaldi claims to be a privacy browser, but it pushes ads to the users whenever possible. For example, the start page tab is filled with pages that have their affiliate links, without asking for the user’s consent. Vivaldi’s ad blocker also whitelists ads that generate revenue for Vivaldi, again without the user’s consent. Moreover, Vivaldi does not have a setting to disable JavaScript; users would have to access the default Chrome settings to do that.( also they keep saying that they don’t want to opensource their browser because then they would fail, while this is very wrong as proven by other opensource browsers)
Overall, I think they are very scummy when it comes to privacy and ethics of consent of ads/affiliation.