Deciding which broker is right for you depends very much on what stage you're at in your career and how much support you need to be successful. There are several questions you should ask when interviewing a broker, such as what type of training is offered for new agents, and what about mentoring or a shadowing program? The next question would be something like, what is the commission split? I think everybody's concerned about what they're going to get paid. Does the commission split change the more transactions you have or the more experience you get?
Don't be afraid to ask those questions of your broker. Does the broker provide leads? Are they actually going to generate business for you? What are the splits then? Are they different than a regular commission split if the broker actually provides that lead? Is there any marketing or advertising support that your broker's going to do for you? Are they going to pay for it out of the box? Are you going to have to split the cost, or do you have to cover it? How much marketing and advertising support are they going to give you?
Do you require agents to work full-time? That would be a question I'd ask. If I was coming from one job into another and I was going to be part time for a while, I'd want to know what the expectation is from my broker.
Beyond interviewing several brokers, you should also ask the agents within the brokerage that you're interested, what it's like to work there. Sometimes the picture painted by the broker isn't the same and may be different when you talk to agents that work at that brokerage.