Context
I've recently been using Gary Fong's Diffuser and I like the results that it gives me on my Metz 64.
I use my flash mostly indoors but also outdoors as well for people shots that can vary from 2/3 body shots to a tight portrait shot. I don't plan to shoot products or related but I might consider it in the future. Depending on the shot I will aim it at the person or bounce it off of nearby walls or ceilings.
Question
When the camera is hanging from my shoulder strap, the front dome OR the diffuser itself has fallen off from my Metz. The dome is a pain to put back on and I've had it fallen off a few times everyday I'm out for a shoot.
Is there any alternative or better diffusers that are recommended, since I want one that stays on but is also big? I was considering the Graslon Insight Dome Flash or a giant soft box on the flash. Or am I just not putting it on right and that's my real problem?
EDIT
Looking for more of a diffuser to bounce off as well as aim directly at the target versus a softbox here or here from the comments below. Doesn't mean I won't try them.
The diffuser I will get is mainly for portraits/group shots related. If I need one for products I'll get a different one.