Larger companies generally have many offices each of which provides guidance and support to it's agents individually. The idea of a "larger" firm, whether it is franchised or a large regional independent firm like mine, is that it can generally afford to provide more services and training for agents. Depending on the company, you may have a "best of both worlds" scenario.
Don't forget to ask about what costs are incurred by the company and what costs you are responsible to pay. That is also going to vary. Do you have to pay for your own agent web site, print ads, etc... or does the company pick up those costs. You need to run to numbers.
As far as the debate over building a listing inventory vs. representing buyers, both are equally important. At the moment, ready, willing, and able buyers are harder to find. But we know the market changes over the years. Your best bet right now is to reach out to everyone you know to let them know you have a great new career that you enjoy...And associate yourself with the company you feel most comfortable with and will provide you will daily hands-on advice.
Again, best of luck!