TL;DR: Robby Russell wanted out-of-the-box functionality for newbies, and auto-updated turned on. Sorin Ionescu wanted better tailoring for experts and didn't w

TL;DR: Robby Russell wanted out-of-the-box functionality for newbies, and auto-updated turned on. Sorin Ionescu wanted better tailoring for experts and didn't want the auto-update which he saw as annoying. Thus the split between the code bases.