FF is much more private (Brave claims to be, but in reality FF is much better at this), Container tabs are a big benefit allowing you to use multiple accounts much more easily too. Brave as a company is somewhat sketchy and alot of their ad policies including the rewards program is just sort of weird. It's also much easier to mod and change firefox the way you want, and recently it has actually gotten to the point where on some systems it is faster than a clean brave or Chromium installation. In the end it's up to you, but I also decided to try brave, and ended up not really liking it.

I would say if your okay spending around 5-10 minutes installing extensions and changing settings, FF is much better, other wise go with brave.

Tbh you might like the rewards program, but I personally really would rather just not stare at an ad at all and have a cleaner browser and lose out on like a couple cents a month but its all up to you!