I've been using Vivaldi since 2016. Switched after Opera got terminally enshittified. Its main advantage is that its UI doesn't change unless changes are genuinely required for new features. Even when they did a redesign a year or so ago, I was only mad for 10 minutes until I discovered a setting to undo it :D There are occasional annoying bugs and performance regressions, and the feedback on bug reports could've been better, but overall, I like it.