I switched from Brave to Firefox recently, and I'm very happy! I perceive it as faster, and feature-wise it's pretty much equivalent. It's made some enormous performance improvements.

Firefox still has some rough issues. It doesn't always feel like a native app (e.g. form fields, toolbar, preferences), and its visual touches (e.g. the main toolbar) are sometimes heavy-handed. In other areas, such as the "omnibar" behaviour, it's still catching up to other browsers, but at least it's catching up.

Another thing I dislike is just how much tweaking I had to do to remove quirks. For example, Firefox has some really excessive animations, which fortunately can be turned off ("ui.prefersReducedMotion" in "about:config").

Firefox has some ways to go, but I'm a lot more optimistic about its future than I used to be.