I feel it is a matter of utility. Soft box lights are very even in illumination, but can be hard to tear down and set up for needed coverage size considerations (except for the smallest ones designed for the intimate wedding couple to be framed, or for on location portraits). Quality umbrellas can offer quick light source multiples, softening light source shoot through, or liners of different types for reflection -- and collapse and assemble without much work. As such, they are more flexible for on location set ups. Bigger soft boxes are mounted to my power pack feed for up to 4 Norman system heads when doing in house or in studio preset and predetermined soft trend lighting according to established in house subject occupancy and fill areas (products, small performance groups, interactive human subjects carefully arranged for composition).
Portability has shifted with monolight digitally adjustable heads and extremely portable battery powered light heads. Power illumination and larger area lighting though comes from power pack lighting systems and their arrays. How much contrast or shadow suggestion for the presentation of subject depth do you need for what you shoot (vs flatter subject presentation with certainty of light coverage and depth)? What does one need for shaping and spreading the light source for a captured image presenting more than a flat affect? Another consideration is where one is placing a light on location. I've seen folks coming into a location, where a light is set up with an umbrella, and knock these over by their presence more than I like to see. So trying an orange ribbon to the stand is sometimes vital. Soft boxes never seem to be bumped as much, so end up on the floor less often than umbrellas.
Also umbrellas and soft boxes come in different sizes for different lighting purposes and illumination needs. Hope this helps.
Last edited by climbmountainway; 11-23-2020 at 05:03 PM.