For a couple of days I have been evaluating where I will go and where I will recommend others to go once Firefox migrates to becoming a watered down version of Chrome (and Cyberfox' last release becomes outdated).
Main contenders have been:
· Iridium
· Brave
· SRWare Iron
· Waterfox
· Pale Moon
· Comodo Dragon/IceDragon
I will go with Pale Moon (http://www.palemoon.org/).
Seems to me it is more customizable, long term viable, open, etc... (or just less broken by design) than the alternatives.