Will step in to say I agree with @Bobotron on the have a mix of roster and the ability to create your own.
I used to think it was pointless to have ready-made characters, but I've been meeting more and more people who really enjoy being able to dive right into a game with a roster character who has connections, history, and some hooks (not necessarily secrets, but hooks into the game). This is good for the people who are more shy and have a hard time integrating themselves.
It'd also be a good idea for the player-made to have them set a flag on themselves whether they're OK being rostered if they disappear, that way you're not having to write tons of people out of the story if they disappear (so you don't have errrrr head of house just languishing away / dying off all the time... but you're also not alienating possible players because 'Ohhh I don't want my own creation being played by someone else if I leave, gross.').