Cindy, think about what happens to the light when you use any diffuser. With any Fongdong it's throwing the light in a 360 degree pattern, which means you're throwing light where it doesn't need to go. Indoors some say this light bounces off surfaces and a portion comes back to the couple, but this would only happen in a tiny room. Really the only thing going for the Fongdong is marketing.
A good diffuser increases the size of the light source. The Fongdong does that, slightly. Outside though just use direct flash as fill, or no flash at all.

