Anything is better than unmodified flash... personally I feel like an omnidirectional modifer like this wastes a lot of the light to the rear and sides, requiring more power from the flash, eating batteries faster, and increasing recycle times.
Depends on the venue really.. a small tight room with good white walls and a low ceiling, this would allow a lot of light to be reflected. A more open venue... I would use something more directional, like a Demb bounce card or similar.