Upload & Sell: On
One of the things I learned from Simon Gerzina (Shatterkiss) before he stopped visiting was that one of the most important aspects of the beauty dish was its opaque center deflector. It allows one to bring the light in really close, for crisp yet wrap-around light, without blowing out the forehead.
Do to the dramatic fall-off of light when using a close source, most lights, if set not to over-expose the forehead (or nose, or whatever), would under-expose the ears or neck.
If you use a larger source from further away, the fall-off over the few inches from front to back of a face isn't so dramatic, so the center deflector isn't needed, but unless it's a really large source you can't get the same wrap as with a BD used close.
Going by Simon's advice, for the classic "BD look" I'd use my 20-inch BD at just 20- to 30-inches from the subject. Five feet or more? It may be a good look, but not what I'd call "the beauty dish look."