Only you can choose which real estate broker is best for you. Schedule interviews with a few of them - see what they have to offer; what fees are involved for you to join their brokerage; if they have training; do they supply leads; how is marketing handled; etc. I may think my office is the best and the agent down the street thinks their office is better - its a personal situation based upon what you are looking for in a broker and what they expect of their agents.
As far as I'm concerned, that answer may be different for different people. I think you really need to go and interview with several agencies to get a feel for what they have to offer and how you feel you'd fit in to their agency. Make sure wherever you go they have a great training program - whether it's formal classes or whether it's one-on-one with the broker. I interviewed with both a large, national brokerage and a small, local brokerage - I chose the small local brokerage because I really liked the broker and the other agents in the office - it really is a family atmosphere and everyone is supportive of one another. For me, this was the right choice. For someone else, they may have felt more comfortable with the formalized training that the national brokerage had to offer. Good luck and please keep me posted.