For any day-to-day browsing, I use Brave with the cryptocurrency bits turned off. I used the "Fennec" version of Firefox for Android for years, since my first smartphone in college, but by the time the GeckoView-based rewrite was released, I just got tired of the poor performance and reduced battery life compared to Chromium. Only one anecdote, but Firefox felt more jittery and made my phone much hotter than Chromium did.
After the UI overhaul, where (IMO) they tried to copy a Chromium-style interface, I ran out of any non-ideological reasons to use it over Chromium-with-an-ad-blocker-built-in.