portable softbox for external flash

Anyone has use a portable softbox mounted to Speedlite?

How's the result? Is it better than using other diffuser?

Or Off camera flash?

I have one that's about 20cm by 10cm, it makes virtually no difference to the light unless you're really, really close. Soft light is about the apparent size of the light source, so a huge soft box 10 meters from the subject will be less effective than a small soft box 1 meter from the subject. All they do is waste light.

I don't use diffusers with on-camera flash any more, I use umbrellas and off-camera flash, or I bounce the light off a ceiling or wall.