Firefox is OK. Slimjet (Chromium based) is the best.
Of the hundreds of operating systems used, only the current version of PCLOS (PC Linux OS) has Firefox easily installed from its repositories.
Unlike most Chromium-based applications, it allows most (all?) of the Chromium extensions to work.
Similar to most Firefox—and Chromium-based web browsers, it allows auto-updating of the settings from either Firefox or Google settings.
Android systems have only limited setting upgrades, compared to the Linux & Windows systems. So Firefox is used, due to Slimjet being unavailable on Android.