stockr, It really depends from where you think that you will draw your client base and what their requirements will be.
Go to the firm that can help you attract the most solid client base.
IMO, limiting yourself to small caps wont be your answer.
MER, most likely still has the best training program. But many other shops do well in that area.
Have you looked into what is required to pass the Series 7? Tough test.
Not trying to discourage you, in fact I miss the biz :)