Brave is great out of the box experience with a lot of privacy toggles enabled by default. Firefox can be hardened a bit more, but it requires more of a user input. Both are great options, so it mostly comes down to which engine you prefer, Blink or Gecko.
Some people also choose to use Firefox for a simple reason if it not based on Chromium to avoid monopolization.
For the most part it really is. A lot of what it does I would do anyway, but it has that by default, which saves a lot of time for me every time I install it (which is quite often due to my endless distro-hopping). Not everything works perfectly, and a lot of that is intentional (such as spoofing the timezone). I would definitely recommend giving it a shot, and if something doesn't work well you can probably just turn it off (and they'll probably explain how in their FAQ).