Technically, an agent sends you out on auditions, not a manager. However, that being said, some managers do have access to breakdown services and/or get actors appointments through their relationships with agents. Some people feel that therefore a manager is "better" because they will send you out through multiple agents, but not all managers do this. (and then of course there is always the question....do u give commission to the agent even if they didnt get you the audition?--I say yes. especially if you value your agent) An agent is still important in negotiating contracts, as a manager does not do this. So I mean, it depends, but i would say generally an agent would get you more auditions. As far as actually booking .....that is your job! an agent or manager doesnt do this for you. They get you the auditions, your talent gets you the job. Good Luck!