The only thing that keeps me away from using Firefox on Android is the, in my opinion, the horrible startpage. I like to have the option to choose my own startpage, such as DuckDuckGo, Bing startpage or something.
The backgrounds you can choose for the 'customizable' startpage of Firefox are not tight and it looks like you see it from a 128x128 pixel phone. The last visited pages are a mess, more pages from the same website are shown (yes, these are visited pages, but why do I have to go back to the cookie settings page or an error 404). Please let the user decide.
Kinds regards,
TechCluster.