I wanted to try out firefox on my android devices and directly noticed quite a few glaring issues. The performance itself is severely lacking on devices capable of 120 Hz. Scrolling feelings decently laggy and janky in comparison to Chrome. Also, there is no good tab management method.
Most extensions aren't available for android devices and the ones that are just aren't enough. There is nothing simple like Chromecast grouped tabs. Also, even using extensions constantly forces you to open extra menus since it's not possible to easily add their buttons to the toolbar.