My experience with Vivaldi was not good. It was always the slowest browser.
Brave was always the fastest.
I don't trust Chrome because it's serving Google, his Evil Master (aka The Money Maker).
I find Firefox the most trustworthy.
Working with Vivaldi right now.
It's alright. Its nowhere near as fast as OG Opera used to be, though it at least feels faster than most other browsers on the market. Vivaldi also has a tendency to tack on unnecessary things and updates bit by bit, the same problem Opera had.
It feels like this is simply the cycle most new browsers go through now. They start out minimal and fast, then slowly fall for the issue of having to validate time spent developing, so they sell out.
(Or alternatively, we stop putting oversized JS frameworks/libs and ridiculous tracking systems inside our pages)
I thought that Opera Unite was magical, and bewilderingly, it was pretty simple. It is my hope that Vivaldi attempts to bring it back.