Keep in mind that choosing a broker is two-way street.  Broker will be interviewing you as well. 

Barbara Todaro has some good advice and Mary Yonkers has an excellent comment..It is a two way street and you will be interviewed too..what do you have to bring to the table?

Mary Yonkers has a great response for you.

interview several.... training and mentoring are most important.... don't dive in unless you know there's water in that pool....

It will depend on whether I were brand new to the business or an experienced agent.

Mary Yonkers nailed this one!

First and foremost - support. Education, Training and if they have mentor or not - followed by split.

When you're new, a great post-licensing training setup in important.

Whether or not they will meet my needs.

One who provides the services that you need.

One with a good mentorship or training program. 

Experience, good terms for me, tech support and reputation. 

I have given a very good answer to you on this already, now I would like to know what you look for?

Positive culture.

One with a good mentoring and training program.

He has to be able to nurture, guide, train & coach

Per the Active Rain staff, this is not a valid use of the anonymous feature.  In addition, how will your teacher know you asked the question?

A record of success and an office that meets your personal needs.

It depends where you are in your career.  Choose wisely.  

If they will buy signs and business cards for you.

Barbara has a good answer.

Like Barbara Todaro said training and mentoring are very important. When they say they have great training, ask for a copy of their training calendar.  If they don't have a calendar they probably don't have any training.

Killer listings.