Prompted by stacking diffusers to further soften the light? I'm aware of the 'bigger is softer' rule for soft boxes & already own a couple of very simple reverse-mounted speedlight umbrellas with white diffuser fronts; vertical 60x90cm, similar to this...
Cheap & cheerful, they seem to do the job.
I'm thinking of going up to 120cm octagonals, but just wondered about two aspects before I do.
I can get the simplest octagon umbrella with white diffuser for £15, add a honeycomb for another 15, or go all out and for 100 I can get deep parabolic.
After that, I'm seeing prices up to 300 for what looks very similar. I assume up there I'm paying for construction/longevity/interchangeable mounts etc, so remove that from the equation.
What is added by a) the honeycomb & b) the extra depth?
I'm assuming each adds "more diffusion", evens out the light better, presumably at the cost of needing more power from the flashes.
I'm tempted towards the honeycombs - probably swayed by the fact I see them in use all the time (I work in the tv/film industry, but nowhere near the camera) but I'm not even sure I'd have the room for the deeper umbrellas or what it would gain me.