The chewy edge is best, IMHO. I've tried so many times to get them to come out that way, but it almost never happens.
My mom bakes hers in a white Corning Ware dish and the edges are chewy every time.
I bake them in a clear glass cake pan and they have more of a heavy cake texture throughout.
The type of pan we use is the only difference I can see between hers and mine.
At the bakery where I used to work, we made brownies for The Original Cookie Company. We mixed cream cheese into the batter. Those were the best brownies I've ever had. The batter was better though.
Barb