I dunno why you wanna be a slave to a stubborn leader thats gonna eventually gonna be stabbed in the back by its own most loyal people and probably whiped out by some kind of plague .Im not saying NCR is much better but at least you can do something there, rather than birth giving you what you can be .The NCR are not heroes but neither the Legion are bad guys .I would go for the NCR ,they dont care who you are .EVERYONE TO THE MEATGRINDER .