Customers most agreed on the following attributes:
Have one for all my flashes...
I had excellent experiences with this accessory. It really soften lights and I suggest everyone to use it in every occasion. I use it even to soften fillflash.
Why didn't I get this before
best all around [$]wonder. I never take it off my flash gun. complements my bounce flash all the time. never fails. with it on, i can hand over my camera to whoever to take any indoor flash photos and results are beautiful, and totally consistent regardless of expertise. All it takes is to raise the bounce head a bit and you're all set. Equally perfect for off-camera flash, get studio quality soft light from your 3 or 4 remote 450EXs..
I admit I haven't used this too much because I didn't like the results the few times I've used it. I think the lighting is best when I bounce my flash off the ceiling or wall. Plus, I don't have to carry this item around. It is also difficult to get on and off (at least initially -- I'm sure it loosens up if you use it more often than I do).