@Scott Schuetz, thanks for bringing a contrasting perspective. My plan is to interview 2-3 big chain brokerages and 2-3 smaller boutique brokerages. I'll be making a list of my interview questions this weekend and calling to set some appointments next week.
My uninformed feeling is that the larger houses may be a "safer" bet, but also may be limiting in some ways. I have prior sales experience, as well as experience in business operations management. I'm guessing that the average new agent usually doesn't have this experience, so training programs of the larger brokerages may be cookie-cut designed to teach some skills I may already have. On the other hand, while I have no problem with initiative and independent motivation, I still know next-to-nothing about the nuances of the RE business, and don't want to set myself up for failure by not having a strong support network in place as I get started.
As you said, I'll be talking to brokerages to see what feels the best and then diving in. Ultimately, I know my success is dependent on me, not with the broker I choose to start with.