Shardik
Still Mildly Glowing
I'll never forget the shit I had to go thru in Fallout 1 and New Vegas just to become a member of the Brotherhood of Steel, nevermind the leader of a freakin' chapter.
That and I loved how the different factions of New Vegas offered me actual incentives and reasons for joining them.
NCR and House of course threw money at me, as well as idealistic jingoism and a grand plan for the future, respectively.
Caesar used an interesting mix of historical knowledge, philosophy, and downright intimidation in an attempt to win me over.
Depending on your character, you could respond appropriately. Some of my more venal characters go with House and/or NCR. My more idealistic ones often go the Yes Man route, and my Legion gal was completely agog by Caesar's philosophical musings.
What motivation do the Minutemen offer the player character for joining them?
A cool laser musket and a funky tri-corner hat you can use to decorate one of your settlement shacks. What more could you possibly want anyway?