I wondered the same thing when making my purchase some time back, and found that the larger dish would provide a softer light. Generally speaking, the broader (bigger) the light, the softer it will be.
Well, thank you! You just generated a sale for Adorama. I have always done some footwork before I purchase something. Specially with things that are in a field as complex as photography lighting. Thank you adorama for having this service to allow us to ask people in the trenches. Again, thank you Gabriel for your quick response!