A bunch of games in the past supported "custom" starts meaning the game would begin in a different place on the map for the character with particular origin, he would get particular bonuses related to his original faction (skill boosts and low-tier factional equipment) and typically would be tasked to complete a quest before he can get on track and start questing in the main line.
Let's say FNV supports custom starts and you can pick a place where you are spawned and have to do a small quest or two before you leave to find work as a Courier and the whole main story ensues.
Who would you pick and why?
"the game would begin with a particular
origin (dragon age: origins)." "Do a quest or two then start the main story(dragon age: origins)"
You are getting references from DA:O, right?
Anyways, I would side with the Brotherhood because I have a lot of respect for them.