Arkenfox can be both heavy-handed (disables search from URL bar, restore tabs from previous session, etc) and hard to digest (1200 lines). By comparison, Betterfox is 250 lines and looks to be more "sane" out of the box.
> disables search from URL bar
Set keyword searches to true:
user_pref("keyword.enabled", true);
That way it uses your default search engine when searching from the address bar.
There are substantial differences in Betterfox compared to Arkenfox. Betterfox causes less breakage and is appropriate for everyday use cases.