I don't run Android anymore, but when I did (about two years ago) I uninstalled Firefox because, as far as I could tell, it didn't properly background tabs when the app was closed. I didn't realize this initially, so I was unsure why my battery life was terrible and my phone as always hot. Being able to install extensions was neat, but not worth it for killing my battery.
Suffice to say, I do not agree that it's the "best mobile browser" on Android.
Suffice to say, I do not agree that it's the "best mobile browser" on Android.