Totally agree. It is the best browser across all platforms of mobile and desktop for me. I read on here all the excuses others make for not using Vivaldi but they don't pass the smell test for me. Long may Vivaldi prosper.
The Vivaldi team have a long history of closed source browser development. I mean I was using Opera almost 30 years ago so I don't have any concerns about it being closed source. But you do you.