How do I find out the REAL history?

[Account Closed]

This is my first foray into this section, and I'm here with a question or two. Or three...
I have two houses to sell, and potentially three to buy.
What reasons would I use the same realtor to list both, and converesly, what reasons should I NOT use the same agent to list both?

One is an agent I've known for years. She helped me purchase my residence that long ago. As a matter of fact, she literally saved the purchase. I believe she's a top agent, and according to her website, she is. How can I find out more about her professional history?
I don't know that I want to use her for listing both sales. She has shown me several houses over the last several months, and I expect I will purchase at least one house through her, possibly two.

The second is an agent I've recently met as part of my interviewing process. She impressed me with her demeanor, her attitude, her information. I have no knowledge of her history, either. Of course this is business, and I want a top closing agent.

How can I find that information?
AND,
I just asked this question in another thread (agents getting rich):
"How do I find out if either of the RE agents I'm considering hiring to sell my house is in that 10-20% that are closing sales?"
Thanks