On camera flash diffuser

[iND]

Not speaking like a true strobist I have times I must have an on camera flash

weddings, weddings, and weddings.

Does anyone want to speak to their preference on

Sto Fen

Gary Fong

Other

Im speaking about medium range indoor photography that does not have the luxury for additional set up.
15-20 feet usually ETTL with a fixed aperture

I've been using the Gary Fong for years but thinking of changing back.
Like to hear some other experiences.